I have dove Cozumel the last 4 yrs as far as sugestions for dive sites my favorite is Punta Sur Devils throat, Columbia shallows, Baracuda reef, Yacab wall, Palancar Bricks,Yacab wall,Palancar caves, these are just some of my favorates. I’m not familuar with the dive shop you use I use Dive with Martin they have the fastes boats so we are always first on the dive spots. We are staying at Park Royal and Dive with Martin is just 5min walk. Make sure you do a night dive or 2 they are fantastic if I ca be of any more help just let me know