Each adjustments applies to the base price, it doesn't happen in series, where it adds 25%, then subtracts 10% of that previous adjustment.
If you're using the priority set at "highest priority only" and you have multiple adjustments and leave them at the same priority (0 being the highest priority and I think that's the default number it's set to) then the one that give the highest price (aka you lose the least amount of money) is the one that will apply.
Pay close attention to what you set for the accumulation and the priority and use the little question marks for help if you want more explanation on those settings!