I have two perculas, a bubble tip anemone and a large frogspawn. The clowns showed no interested in either the BTA or the frogspawn for a long time. They mainly hosted in the bottom corner of the tank. Then one day I decided to rearrange the tank and pull out some rock and all of a sudden, the clowns discovered the BTA and started hosting it like crazy. Then for some reason, they started hosting the frogspawn as well and to be honest, I think they like the frogspawn better than the BTA. I suspect it is because the frogspawn is much larger than the BTA. But they do host in both. So, you never know if/when/what will happen! But if you are not getting the result you want, try moving some things around in the tank!
Good luck!
Pat