So not only to you have to find out for sure what the parties want to agree to (including the relevant issues below the surface), but you also have to write it in bulletproof form.
This is why lawyers get called deal-killers: they sometimes wind up forcing clients to realize that they can't do what they want.
Poorly drafted contracts are a dime a dozen: the caselaw is littered with them.
This is apparently trying to create a "cost plus" agreement. It's bad: grammar and punctuation aren't helpful.
Some tips: