OKI Print Control software for working out print costs

[UKDarkstar]

I'm using an OKI C3520MFP at home and have been asked to run a print job off for someone. I need to know the costs to work out what to charge them.

 

I've installed the OKI Print Control software and it seems to be working ok and pulling in the printer log but despite playing around with the settings for fees it seems to be telling me that the toner cost per page is the same regardless of what I print and coverage.

 

Anyone have any experience with setting this software up and using the fees setting to work out the cots of a print job ?