diff --git a/docs/Engineering_Reference_Manual.md b/docs/Engineering_Reference_Manual.md
index cb99c593..66773ddf 100644
--- a/docs/Engineering_Reference_Manual.md
+++ b/docs/Engineering_Reference_Manual.md
@@ -396,9 +396,9 @@ The couple keyset is a Tink AES-256-GCM keyset generated once per couple.
 
 - `RecoveryKeyManager.newCoupleKeyset()` creates the keyset.
 - `RecoveryKeyManager.wrap(keyset, phrase)` derives a 32-byte key with Argon2id:
-  - **memory**: 46 MiB (`46080` KiB)
-  - **iterations**: 3
-  - **parallelism**: 1
+  - **memory**: 46 MiB (`46 * 1024 = 47104` KiB; constant `ARGON2_MEMORY_KB`)
+  - **iterations**: 3 (`ARGON2_ITERATIONS`)
+  - **parallelism**: 1 (`ARGON2_PARALLELISM`)
   - **salt**: 16 random bytes
 - The keyset plaintext is encrypted with AES-256-GCM using the derived key. AAD is the fixed string `"closer_couple_key"` so the blob is portable across invite-code reconciliation.
 - The wrapped result is stored on the couple document as `wrappedCoupleKey`, `kdfSalt`, `kdfParams`.