Postgres array types

I have a application which maintains a number of monthly totals.

recorded, mth1, mth2, mth3 .... mth12, total

This from the days when I used another DB system to postgresql.

Is there going to be a performance advantage to change to using
postgresql array based datatype for these records? Particularily the
general ledger totals are retrieved enmass and then used to present the
profit/loss + balance sheet. Would retrieval times be improved?

I am writing the front end with delphi+zeos.

any input appreciated.