I think once you’ve turned it on once it should stick in future.
It’s not necessarily as simple as a single “paid” date as one payment can be applied to many invoices and/or many part-payments can go towards one invoice. I guess it might be possible for the QuickFile devs (I’m not one of them!) to add a date in cases where it’s one payment for the whole invoice, and the “view all payments for this invoice” link when it isn’t, it’s a question of how many more database lookups that would entail for each page view and whether it’d slow things down too much.