One thing I discovered about the app
So if you open it when there is some promo, where you get points, and a scratch appears only take one swipe. If it is anything less than 100 tap the navigation button (three lines) on your phone. Then just tap the app window and the scratch is brand new. Keep doing until you get the desired amount.
Granted I have not checked to see if it worked at the register as I really had nothing to buy, but hey you lose nothing.