We don't normally cut cabinet parts for others, but I believe we charge about $125/hour for machine time. I can normally cut 8-10 sheets/hour of nested cabinet parts. If you can only cut 3-4 sheets, you really can't charge the same as someone that's much more efficient.
What I'd recommend is charge for nesting as a separate item. Who's programming the parts? What nesting software do you use, and how long does it take?
Basically, you break down the time needed for programming, receiving, stacking and loading, and add all those costs to the machine time cost.
Doesn't a 315 have pods? I used to program and run a 327 for about 12 years.