i have been having the same problem as the many people have that the sales liability report does not even closely match the Sales by product/service report. And, NONE, I repeat NONE of the reason's for why this discrepancy apply to my situation. Nice try but the truth is there is something, possibly many things with the way QB calculates Sales Tax Liability.  You seem to be right about one thing, its not retreiving its data from a place consistent with where sales is retrieving its data. Sounds like a QB problem and blaming it on other things doesn't help the millions of people trying to  pay the correct amount of taxes.

I could not have a simpler business structure. I simply have 4 areas that I can receive income Non-tax services, non tax shipping charges, and only two accounts that make up my taxable sales. I never give refunds or credits all sales are final.  Yet the total sales for each of the 4 catagories come in about 25% off. This is not a small amount.  

If you cannot be forthright about where the problem is or even how to fix it. How should we file our TPT taxes. Should we use the Tax Liability Report which shows less or the Sales by product/service totals?

Please tell us mistified people what is the right report to report on. 

Linda