If you want to hire
you gotta pay for that.
Would you rather have an hourly rate of $100, but an estimation for 30 hours effort and maybe a worse outcome?
I find the $150 steep, too, but it’s not extraordinarily high for a professional contract - on the contrary!
$3,000 for the complete rework the support and the documentation sounds fair after what I’ve read here.
…there are other places at which Nu needs to save money - especially in terms of ongoing costs and not one time efforts 