I thought the same was happening to me, but I think I figured it out. Before entering the box 10 information the full $6000 is considered for the dependent care credit. Once the $5000 (or whatever amount you have) from box 10 is entered into Turbo Tax, this takes away from the amount that is eligible for the dependent care credit (because it was taken as a pretax credit during the year) and lessens the overall tax return. Hope this helps.
