It would not be a good idea to have both on the same day if you hadn't had reflex before as you need to gaugue your reaction.
If you are used to both therapies, I dont think it would hurt. I often give clients an IHM and reflex consecutively to good effect, also may give them a brief back or knee massage if appropriate. I reduce the treatment times tho, not 2 full sessions, otherwise I'd need a massage and reflex
jan