Anyone have experience using a Shimano STI triple with a compact double crankset? My LBS built out my Ultegra SL gruppo that way, and is saying using the triple shifter is no big deal and can give me more trim ability. I'm skeptical, as it takes two clicks to shift, and the first shift is too much movement for 'trim'. Is this mixing of the components a common practice, or am I having the wool pulled over my (new the road world) eyes?

TIA for any help sorting this out.