There are cheaper cloud mining options compared to GM. More importantly, there are options where you can not only get cheaper hash but also you can SELL you hash at a specific time period which decreases your ROI significantly.

For example, I can reach 70% of ROI, then sell the rest of my hash and be in profit. All this depends on a lot of variables but I m just pointing it out so you can have an idea how important it is.

GM, if I were you, introducing some form of internal market for selling hash would be my top priority. All this under assumption you are not afraid everyone who currently owns your hash would immediately try to dump it and leave. In this case, you have more important problems.