Two minor points:

If he has to replace the programmer 5 years from now, that programmer will not have the knowledge or the tools to develop in VFP 5. (Try developing FPW 2.6 on most 333 MHZ or higher).

A year from now and later you will be charging him more time to "re learn" VFP5 and "un-learn" what you then take for granted in VFP 7 or whatever.

C.R.