I want a tax accountant that gets a commission, say, similar to...

I want a tax accountant that gets a commission, say, similar to the commission scheme you pay on trades

Ie, if u get a return under $5,000 you pay flat fee of $XXX, anything over that you pay a 5% commission. (Or so)

Gives them an incentive to increase your return yes?

I would think however that most investors that are doing well will be paying tax not getting it back. I'm happy to pay tax (that is the minimum I can legally pay). More I pay better I must be doing!