We have found that gross product sales are fluffed too much and won't give you an accurate view of your profit, so InventoryLab shows you Ordered Product Sales instead.
To compare your Sales with InventoryLab to Amazon, you will first want to run a Date Range Summary report from Seller Central
First, visit Seller Central and click on Reports. Select Payments from the dropdown box
Choose Date Range Reports from the tabs and click on Generate Report
Select Summary, then choose what range of dates you would like the report for, and click Generate
Note: You will only want to run a report for dates in which all of your orders show as Reconciled inside of InventoryLab for accurate comparison
Your report will now be In Progress. Give it a moment and click the Refresh link
You will now be able to click Download to download the Date Range Summary in .pdf format
Open the downloaded .pdf and add together the Product sales (non-FBA) and FBA product sales lines
Next, go to InventoryLab and click on the Reports tab. Choose Profit & Loss from the dropdown menu
Select the same exact date range that you did when you ran the Date Range Summary report and click View
Compare the total in the Sales line to the total you received when you added your sales lines together from the Date Range Summary report - they should match!
Note: If you ran promotions that included money off the price of your item (not shipping), there may be a difference that is accounted for when you subtract the Promotional Rebates line on your Date Range Summary report from the sales total on that report.