Right after we updated the Ubercart module to 2.10, our product kit module did strange things. First, if you add one item to the kit and save, the total price stays the same. If you change the total price manually, you get an appropriate number added or subtracted to/from the price of the one item showing on the "edit" page.
If you add another item to the kit, not only does the product kit "total price" change on its own but the +/- amount starts changing drastically with every save of the item.
Product A price = $5.00
Product B price = $1.00
When product B is added to the kit, the total price changes on it's own to $15.00. The product A price gets an offset (discount) of $+7.50. The product B price gets an offset of $+$1.50.
If you click SAVE again, the total price changes to $45.00. The product A offset changes to $+32.50 and product B changes to $+6.50.
I think this is a script problem vs a database problem.