I think it's meant to be April.
Anyway, I don't understand why there is such inconsistency in processing passport renewals.
For a start, they're lodged at larger Australia Post offices Australia-wide so must firstly arrive at the Passport Office for processing.
Inevitably despite checking by postal officers, some forms have mistakes.
Others may be an attempt at fraud. We don't know how often, but despite checks and balances, including new passport designs that strike me as extremely difficult to replicate, never underestimate crims.
On some, writing may be difficult to discern. If you had a pile to process, I'd guess they'd suffer a delay as they should because our job when completing the form is to be clear with the fine detail.
And even when processed and sent, a passport to a Sydney or Melbourne suburb is going to take less time to be delivered than one bound for a Rural Mail Delivery in remote Queensland or Western Australia.
From recent use, I was very satisfied with the speed. Far better than I'd expected, given that a fair number of previously regular overseas travellers must be applying for passports even if some won't use them for a few months.