In the browse category on the site, games that are on sale but have a free version don't display the "-xx%" label, so it looks like the game is not on sale.
I use the reverse sale option, and would like to either chose which price to display on the store during the sale (the paid version of the game) or the possibility to easily make the game not free during the sale (just set the sale price without changing the minimum price and having to set things back after the sale).