Deepstacked headsup SNGs are low variance and high skill. Ive played several hundred of these and shown to be a winner at them, but have since switched to cash games. Anyways though, at these lower levels winning 75% may be sustainable, but youd have to be very skilled at these and have a ton under your belt, and if you could sustain that then you should be playing higher. Id try to punch out a good amount of these to get a better idea of where you stand and then go from there. These are definitely beatable, but to show real profits you need to play a lot.