diff --git a/addons/laundry_management/migrations/19.0.19.0.2/post-migrate.py b/addons/laundry_management/migrations/19.0.19.0.2/post-migrate.py
new file mode 100644
index 0000000..1d056d6
--- /dev/null
+++ b/addons/laundry_management/migrations/19.0.19.0.2/post-migrate.py
@@ -0,0 +1,75 @@
+"""Phase 1 financial model migration.
+
+Before: laundry_order.amount_paid was blindly copied from pos_order.amount_paid,
+which includes Customer Account / pay-later payments. Every deferred sale
+appeared fully paid → amount_due was always 0 → Settle Dues was non-functional.
+
+After: amount_paid_cash + amount_deferred are computed from pos_payment rows,
+classified by pos_payment_method.split_transactions. amount_due is recomputed
+as amount_deferred - amount_settled.
+
+This script rebuilds the split for every existing laundry.order by replaying
+its linked pos_order's payment history.
+"""
+import logging
+
+_logger = logging.getLogger(__name__)
+
+
+def migrate(cr, version):
+    if not version:
+        return
+
+    _logger.info('laundry_management: rebuilding financial split for existing orders')
+
+    # Ensure the new columns exist (ORM will have added them, but be defensive)
+    cr.execute("""
+        ALTER TABLE laundry_order
+            ADD COLUMN IF NOT EXISTS amount_paid_cash numeric DEFAULT 0,
+            ADD COLUMN IF NOT EXISTS amount_deferred numeric DEFAULT 0;
+    """)
+
+    # Rebuild amount_paid_cash / amount_deferred per laundry order
+    # from pos_payment rows classified by pos_payment_method.split_transactions.
+    cr.execute("""
+        WITH classified AS (
+            SELECT
+                lo.id AS lo_id,
+                COALESCE(SUM(CASE WHEN pm.split_transactions = FALSE THEN pp.amount ELSE 0 END), 0) AS cash,
+                COALESCE(SUM(CASE WHEN pm.split_transactions = TRUE  THEN pp.amount ELSE 0 END), 0) AS deferred
+            FROM laundry_order lo
+            LEFT JOIN pos_payment pp ON pp.pos_order_id = lo.pos_order_id
+            LEFT JOIN pos_payment_method pm ON pm.id = pp.payment_method_id
+            GROUP BY lo.id
+        )
+        UPDATE laundry_order lo
+           SET amount_paid_cash = c.cash,
+               amount_deferred  = c.deferred,
+               amount_settled   = COALESCE(lo.amount_settled, 0)
+          FROM classified c
+         WHERE c.lo_id = lo.id;
+    """)
+
+    # amount_due is a stored compute (amount_deferred - amount_settled).
+    # Populate it directly here so the values are correct before the ORM
+    # recomputes (ORM recompute on install will overwrite with same result).
+    cr.execute("""
+        UPDATE laundry_order
+           SET amount_due = GREATEST(
+                   COALESCE(amount_deferred, 0) - COALESCE(amount_settled, 0),
+                   0
+               );
+    """)
+
+    cr.execute("""
+        SELECT COUNT(*),
+               SUM(amount_paid_cash),
+               SUM(amount_deferred),
+               SUM(amount_due)
+          FROM laundry_order
+    """)
+    row = cr.fetchone()
+    _logger.info(
+        'laundry_management migration: %s orders — cash=%.2f, deferred=%.2f, due=%.2f',
+        row[0] or 0, row[1] or 0.0, row[2] or 0.0, row[3] or 0.0,
+    )