BK skimmers have bubble plates allowing them to put more air and water through the body than an equivalent Euroreef/ASM. This is true of all skimmers with bubble plates and reaches its height of potential with the Supermarin dual cone body which blasts INSANE amounts of air into a comparatively small body (2000lph/4000lph, 22" tall 10" dia body...)
Finally, I'd wager that contact time is less relevant than reduced turbulence, y'know, the whole quantity vs. quality arguement
. Bit I digress, mainstream skimmers have undergone enough testing that I doubt one would have to worry about any particular unit getting too much water/air through the body.