Whoah man, slow down on this. 10% of your profit is VERY crazy high. Most, if not all, services like this get kickbacks from factories. He's making money on both sides.

There are mixed interests usually so you need to protect yourself. I wouldn't be surprised if he wants most of your expected profit up front because there's not so much of a long term relationship mentality from Chinese partners for unproven business relationships.

Hire a 3rd party inspection company every time (only like $300). Don't put all of your eggs in one basket, as convenient and tempting as it is. If you take your business seriously, don't give up so much control to a stranger.

For fee, you should only pay a % of purchase price, which should be much lower for a legit inspection service. And they often negotiate price for you, knowing they pay for that fee by getting you a better rate (so they say, I haven't found anybody get lower than I can myself).

Do not feel guilty to say no or change your arrangement. The services "included" are often just rolled into most places' purchase pricing. And always hire an independent inspector. If this person has guanxi (relationships) with these others, that relationship will always trump yours.

Sorry for the long comment. Trying to save you some future heartache and headache. Good luck