pgartner,
At this point I would have to say you have two options.
1. Export the information into an Excel Spreadsheet and create formulas to do what you want.
2. Sell them a real call accounting package.
The built-in PSTN logs are not really that robust, but I have seen some pretty nice Excel spreadsheet setups that our customers use that can do a real good job. I guess at some point it might behoove me to create a nice one, but then again it might reduce our number of CSM packages sold; hmm.
Thanks,
TE