So you are telling me that in the (I assume) USA companies would base your offered salary on your previous income and ask for pay stub as a proof?
Okay, I'm living in low income country and workers rights are far from perfect but no company, I mean abdolutely NOONE would have the audacity to check how much was your salary and use it to determine your new pay. Here they'd ask what are your financial expectations, you'd give them the numbers and if they can meet them they'd invite you for an interview. If they can't, they'd sometimes try to offer you less and it's up to you if you agree or not.
Seriously why is this perverse, repulsive practice even accepted in the US?
Why don't you say that you can only pay 20% more for university tuition than your parents did?