It is 30% over and above the lowest price (which can include 20% already)!
It's a great deal if there's something you like. The factory stores mostly carry items manufactured JUST for those stores, but they also carry a limited number of Coach Boutique store items, both current and close-outs. A couple of weeks ago I was able to use a 30% off coupon on top of 20% off an already discounted price for a Large Madison Sophia satchel that is part of the current regular Coach store collection. Retail $598, outlet $220.