My contract stipulates 1st payment, 30% "at completion of excavation".

On the back, however, it states that "Approval of work by an inspecting governmental agency is deemed to be completion of that work."

The pool company wants me to make my payment now, after excavation. I'm arguing that I shouldn't have to make the payment after the 1st inspection (which is excavation and rough plumbing.) as it is not completely certain that the excavation/siting of the pool is properly completed until inspected.

I wouldn't normally care, but we had some permit issues with regard to the siting of the pool which is making me quite nervous about the first inspection.

Do I have a legal leg to stand on refusing to make my first payment until after the inspection based on those wordings?

thanks