New Fee increase: When is fee payable?

[Tired Traveler]

Hi there, with the new Fee increase coming in for many of the visas I have a question regarding payment. In some countries online applications can be done but payment has to be made at the embassy/visa centre. If someone submitted an online application and paid the fee online with for instance their debit card the day before the fee increase they save themselves some money as they would pay the old fee.

If you take someone who is in a country where they can apply online but can't pay online and assuming their biometrics etc is 1 or 2 weeks after the online application would they pay the new fee at the embassy since the date they are paying is after the fee increase or do they pay the fee at the embassy based on the date they made the online application?

If they have to pay the new fee due to no online payment option for their country doesn't that put them at a disadvantage? Or does immigration really care about that!