Alternatively, Hana left it plain in his face unciphered to see if he could even tell the difference between single-entry and double-entry accounting.

Not that the journal entries themselves relay the mechanics behind the calculations, which she did not write down for a summary ledger. Ergo leading to it at first look ciphered, when it really just works on a different system entirely.

Whichever way this goes, I'm open to interpretation.