Actually, while in the water itself the main rate of oxidation of swimsuits, skin and hair is proportional to the FC/CYA ratio so there shouldn't be much difference between 3 ppm FC with 40 ppm CYA vs. 6 ppm FC with 80 ppm CYA. However, when you get out of the water, it is the FC level that matters in terms of how long it continues to react with your sweat to form chloramines that can smell so from that point of view you are correct that lower would be better.

Remember that the FC/CYA ratio relates to the rate of the chlorine reactions while the FC by itself relates to the capacity or available reserve of chlorine so how long it will continue to react once you leave the pool. And yes, as the water evaporates when you leave the pool the concentration of chlorine increases which is probably why the higher FC levels are associated with faster fading of swimsuits -- it's not a rate issue (i.e. not FC/CYA related), but a capacity issue once you leave the pool.