machine billing rate

I know this is in the wrong area but I wanted as much feedback as possible... when billing, how many of you have a seperate hourly rate for your CNC milling centers in comparison to your ProtoTrac mills? My questions are does anyone double the standard rate to run a part on the CNC, knowing it will be done in half the time,,or does the rate remain standard knowing you can run twice as many parts? I am in a new sales position at a shop and they are talking of doubling the standard rate for Milling Center work which does not make sense to me when you can do more volume... Im looking for feedback on both sides.. Thanks everyone for your time in advance

[codyst]

It depends on what exactly you're doing. If you're running the same part day after day doubling the cost doesn't really make sense. Production runs tend to have a moderate to high start up cost, but the repeat work typically allows for low cost on the final product.

Now, if you're constantly tearing down and setting up to run one off's, it makes sense to double the price, because there's typically a fair amount of set up time, part programming and debug, etc. Not to mention the added cost of having to build custom hold down tooling when necessary.