Look at your groups, don't go by brand, but by they're active ingredient. Have a chat to vet, he ll probably ask you to do a worm count to see what you are targetting.  
Eta.  If they ve not been done for fluke, it's a possibility it s there.  Don't think it comes up on fec either, not sure, but I'm sure some one will clarify yay or nay.  Speak to vetin'ry