I am still debating which lights to use. I noticed when looking on Halo's website that they have a different part number for fixtures using the two different bulbs. I have always been under the impression that CFL bulbs can be used in standard fixtures. Why would the manufacturer have a different part number for the two different type of bulbs? Any ideas? Thanks for your help.

Actually, I have never seen a recessed can with CFL as a listed bulb type, but know they are acceptable.

CFL may fitting to a fixture but that doesn't mean it will work properly as the maker designed it. You can screw a CFL into your coach fixture outside but that doesn't mean it will work well year round. I think the cans are different because the heat from the bulbs are different.