Last Friday Night, The One That Got Away and Wide Awake were all discounted for 1-2 weeks.
E.T. was the only single to have a remix that made any impact (LFN's and TOTGA's have both sold less than 100k to date).
Tons of artists discount their singles and don't see the success of TD's singles. If you want to shade Katy, at least come with some new material. This argument is so 2011.