first you need to learn how Sec 8 works...
sec 8 is a rent assistance program under HUD, if tenant has no income or very low income, HUD will pay full rent, if tenant works or get SS income, they much pay up to 40% of the earning toward rent.
but if you accepting rent outside of the HUD contract, it is illegal, HUD can sue you to repay all money back.
now, focus on the word RENT, the contact said you can't accept more rent than what your lease said, but it didn't say it is illegal to take additional deposits, damage repairs, pet fees....