It is unfair to change the rules at the end of the campaign, especially in such important details as personal data and documents, such essential changes should be warned in advance, this shows respect for the work of the bounty hunters.
I experienced that change of rules that definitely unfair to the bounty hunters. Most of the bounty managers prefer to use the stakes system for bounty payments. As far as I am concern, that system cheats! Not everyone can calculate accurately how many tokens one will receive at the end of the bounty. I prefer by far the fixed amount system so we know that for a certain period of work, this is what we will receive.
If they have to change it in the end, maybe the best way to do is a fixed payment instead so it will be easy to calculate the unforeseen circumstances that may occur at the end of the campaign period.