diff --git a/packages/expense/src/data/index.ts b/packages/expense/src/data/index.ts
index ee188f9..363b42d 100644
--- a/packages/expense/src/data/index.ts
+++ b/packages/expense/src/data/index.ts
@@ -8,12 +8,13 @@ import { ExpenseLine } from '../objects/expense_line.object';
 
 /**
  * Seed data — covers the full template surface:
- *   • 6 categories with soft per-transaction limits
+ *   • 8 categories with soft per-transaction limits (incl. Mileage, Telecom)
  *   • 5 reports spanning every lifecycle state + the approval threshold
  *   • 13 lines whose amounts match each report's total_amount
  *
- * Report totals are set explicitly so seeding stays consistent without
- * relying on the line rollup hook (hooks fire on user edits, not seeds).
+ * Report totals are set explicitly because `total_amount` is a stored header
+ * field maintained at the top level — there is no line rollup hook (a nested
+ * parent write from a line hook crashes the sandbox; see CHARTER.md).
  */
 
 const categories = defineSeed(ExpenseCategory, {
@@ -50,6 +51,14 @@ const categories = defineSeed(ExpenseCategory, {
       per_txn_limit: 1000,
       active: true,
     },
+    { name: 'Mileage', code: 'MILEAGE', gl_account: '6440', per_txn_limit: 500, active: true },
+    {
+      name: 'Telecom / Phone',
+      code: 'TELECOM',
+      gl_account: '6700',
+      per_txn_limit: 150,
+      active: true,
+    },
   ],
 });
 
diff --git a/packages/expense/src/flows/expense_approval.flow.ts b/packages/expense/src/flows/expense_approval.flow.ts
index cd613d3..f991dd7 100644
--- a/packages/expense/src/flows/expense_approval.flow.ts
+++ b/packages/expense/src/flows/expense_approval.flow.ts
@@ -10,6 +10,10 @@ type Flow = Automation.Flow;
  * and suspends the run until the expense-manager decides. It then resumes down
  * its `approve` or `reject` out-edge.
  *
+ * Amount-tiered routing: the manager signs off first; claims ≥ $1,000 then
+ * escalate to a finance-director second sign-off before final approval. Smaller
+ * claims are approved on the manager's decision alone.
+ *
  *   approve → status = approved, notify the employee
  *   reject  → status = rejected, notify the employee to fix and resubmit
  *
@@ -52,6 +56,28 @@ export const ExpenseApprovalFlow: Flow = {
         },
       },
     },
+    {
+      id: 'needs_director',
+      type: 'decision',
+      label: 'Large Claim (≥ $1,000)?',
+      config: { condition: 'record.total_amount >= 1000', conditionDialect: 'cel' },
+    },
+    {
+      id: 'director_signoff',
+      type: 'approval',
+      label: 'Finance Director Sign-off',
+      config: {
+        approvers: [{ type: 'role', value: 'expense_director' }],
+        behavior: 'first_response',
+        lockRecord: true,
+        escalation: {
+          enabled: true,
+          timeoutHours: 72,
+          action: 'notify',
+          notifySubmitter: true,
+        },
+      },
+    },
     {
       id: 'set_approved',
       type: 'update_record',
@@ -102,10 +128,41 @@ export const ExpenseApprovalFlow: Flow = {
     {
       id: 'e2',
       source: 'manager_signoff',
+      target: 'needs_director',
+      type: 'conditional',
+      label: 'approve',
+    },
+    // Manager-approved: large claims escalate to the finance director; small
+    // claims are approved outright.
+    {
+      id: 'e2a',
+      source: 'needs_director',
+      target: 'director_signoff',
+      type: 'conditional',
+      condition: 'record.total_amount >= 1000',
+      label: '≥ $1,000',
+    },
+    {
+      id: 'e2b',
+      source: 'needs_director',
+      target: 'set_approved',
+      isDefault: true,
+      label: 'within manager limit',
+    },
+    {
+      id: 'e2c',
+      source: 'director_signoff',
       target: 'set_approved',
       type: 'conditional',
       label: 'approve',
     },
+    {
+      id: 'e2d',
+      source: 'director_signoff',
+      target: 'set_rejected',
+      type: 'conditional',
+      label: 'reject',
+    },
     { id: 'e3', source: 'set_approved', target: 'notify_approved', type: 'default' },
     { id: 'e4', source: 'notify_approved', target: 'end', type: 'default' },
     {
diff --git a/packages/expense/src/objects/expense_line.object.ts b/packages/expense/src/objects/expense_line.object.ts
index a1e0d85..3bacb3f 100644
--- a/packages/expense/src/objects/expense_line.object.ts
+++ b/packages/expense/src/objects/expense_line.object.ts
@@ -5,8 +5,12 @@ import { P, F, tmpl } from '@objectstack/spec';
 
 /**
  * Expense Line — one out-of-pocket item on a report (a meal, a flight, a
- * taxi). Lines belong to exactly one `expense_report`; their `amount`
- * rolls up into `expense_report.total_amount` via the line hook.
+ * taxi). Lines belong to exactly one `expense_report`. Their `amount`
+ * contributes to `expense_report.total_amount`, but that header total is a
+ * STORED field maintained at the top level (client/seed) — NOT a rollup hook:
+ * a nested `update` of the parent from a line hook re-enters the QuickJS
+ * sandbox and crashes the runtime. See CHARTER.md ("Rollup vs. lifecycle
+ * hooks").
  *
  * Policy in v0 is deliberately light: a fixed receipt-required threshold
  * (`needs_receipt` ≥ 75) plus the category's soft per-transaction limit.
@@ -67,6 +71,13 @@ export const ExpenseLine = ObjectSchema.create({
         { label: 'Personal — Other', value: 'personal_other' },
       ],
     }),
+    reimbursable: Field.boolean({
+      label: 'Reimbursable',
+      defaultValue: true,
+      group: 'detail',
+      description:
+        'Uncheck for personal / non-reimbursable items. The reimbursable header total should exclude these (maintained client-side; not a hook rollup).',
+    }),
     needs_receipt: Field.formula({
       label: 'Receipt Required',
       group: 'receipt',
@@ -94,7 +105,7 @@ export const ExpenseLine = ObjectSchema.create({
 
   titleFormat: tmpl`{{record.description}}`,
   displayNameField: 'description',
-  compactLayout: ['description', 'category', 'amount', 'expense_date', 'merchant'],
+  compactLayout: ['description', 'category', 'amount', 'reimbursable', 'expense_date', 'merchant'],
 
   validations: [
     {
diff --git a/packages/expense/src/objects/expense_report.object.ts b/packages/expense/src/objects/expense_report.object.ts
index 2b8c43f..7578a8a 100644
--- a/packages/expense/src/objects/expense_report.object.ts
+++ b/packages/expense/src/objects/expense_report.object.ts
@@ -4,8 +4,10 @@ import { ObjectSchema, Field } from '@objectstack/spec/data';
 import { P, F, tmpl } from '@objectstack/spec';
 /**
  * Expense Report — the reimbursement claim an employee submits. It is a
- * header over one or more `expense_line` rows; `total_amount` is rolled up
- * from those lines by the `expense_line` afterInsert/Update/Delete hook.
+ * header over one or more `expense_line` rows. `total_amount` is a STORED
+ * header field maintained at the top level (client/seed), NOT a line-hook
+ * rollup: a nested parent `update` from a line hook crashes the QuickJS
+ * sandbox. See CHARTER.md ("Rollup vs. lifecycle hooks").
  *
  * Approval is threshold-driven: `approval_required` flips true when
  * `total_amount >= 1000`. Below that, a manager can still approve, but the
@@ -84,7 +86,8 @@ export const ExpenseReport = ObjectSchema.create({
       group: 'financial',
       min: 0,
       defaultValue: 0,
-      description: 'Sum of line amounts. Maintained by the line rollup hook.',
+      description:
+        'Sum of line amounts. Stored header field maintained client-side/seed (not a line rollup hook — that crashes the sandbox; see object docstring).',
     }),
     approval_required: Field.formula({
       label: 'Approval Required',
diff --git a/packages/expense/src/sharing/index.ts b/packages/expense/src/sharing/index.ts
index 2e6e801..b8196ef 100644
--- a/packages/expense/src/sharing/index.ts
+++ b/packages/expense/src/sharing/index.ts
@@ -1,20 +1,26 @@
 // Copyright (c) 2026 ObjectStack contributors. Apache-2.0 license.
 
 /**
- * Three-tier role hierarchy. Higher tiers inherit lower-tier grants.
+ * Role hierarchy. Higher tiers inherit lower-tier grants.
  *
- *   expense_admin → expense_manager → expense_employee
+ *   expense_admin → expense_director → expense_manager → expense_employee
  *
- * `expense_manager` is the approver pool referenced by the approval
- * process and the notification flows.
+ * `expense_manager` is the first-tier approver; `expense_director` is the
+ * second-tier approver for large claims (≥ $1,000) — see
+ * `expense_approval.flow.ts`.
  */
 export const RoleHierarchy = {
   roles: [
     { name: 'expense_admin', label: 'Expense Admin', parentRole: null as string | null },
+    {
+      name: 'expense_director',
+      label: 'Finance Director',
+      parentRole: 'expense_admin' as string | null,
+    },
     {
       name: 'expense_manager',
       label: 'Expense Manager',
-      parentRole: 'expense_admin' as string | null,
+      parentRole: 'expense_director' as string | null,
     },
     { name: 'expense_employee', label: 'Employee', parentRole: 'expense_manager' as string | null },
   ],
diff --git a/packages/expense/src/translations/en.ts b/packages/expense/src/translations/en.ts
index 2000d61..cfbf6b0 100644
--- a/packages/expense/src/translations/en.ts
+++ b/packages/expense/src/translations/en.ts
@@ -101,6 +101,7 @@ export const en: TranslationData = {
             personal_other: 'Personal — Other',
           },
         },
+        reimbursable: { label: 'Reimbursable' },
         needs_receipt: { label: 'Receipt Required' },
         receipt_attached: { label: 'Receipt Attached' },
         notes: { label: 'Notes' },
diff --git a/packages/expense/src/translations/zh-CN.ts b/packages/expense/src/translations/zh-CN.ts
index 32da41a..dba65c6 100644
--- a/packages/expense/src/translations/zh-CN.ts
+++ b/packages/expense/src/translations/zh-CN.ts
@@ -86,6 +86,7 @@ export const zhCN: TranslationData = {
           label: '支付方式',
           options: { personal_card: '个人卡', cash: '现金', personal_other: '个人 — 其他' },
         },
+        reimbursable: { label: '可报销' },
         needs_receipt: { label: '需要票据' },
         receipt_attached: { label: '已附票据' },
         notes: { label: '备注' },