I will certainly not disagree with Ronald, as I certainly haven't been able to find any way to leave the invoice numbers out of the Product Detail Report. If you're willing and able to work with spreadsheets, though, there is a way to approach this outside the program. This is the part I especially like about EZP - you have a lot of different ways of working with the data, rather than it all being locked down as it is in most other software. But it does require some experience with spreadsheets.
I generate a Product Detail Report every month to find out what to pay our consignors. I generate the report and "save" it (it will save in .txt format). Then, using a program like Excel, I open the file, and a "text conversion wizard" pops up to do the conversion. Once converted, you'll see that the invoice numbers are all on separate lines than the rest of the data. So then I'll sort the entire report by date, which results in the entire upper half of the report being data I'm interested in, and the lower half all being lines of invoice numbers. Then I just delete all the lines of invoice numbers - all at one time. Then I'm left with nothing but lines of data I use for my final report, and can sort everything by whatever I want - by Product Description, Vendor, Price, or anything else - with nothing else to get in the way.
Again, I'm not disagreeing with Ronald in the least. But there are workarounds if you're willing to go a few extra steps. And for all the other things EZP does for us, this particular workaround is very minor.