as im sure you know, LSx cars have a low octane timing table and a High octane timing table which switches back and forth according to the octane rating (87 low, 93 high)
well, my Low octane and High octane tables are the same for easier tuning reasons. IF the gas is on a winter mix like you claim, then my car for sure would pick up some KR sense the only thing it knows to go by is 93+ octane.