LHH

i do not know what year LS you have, but on the 2016 you have the option to select " individual presets" not "mixed presets" and you will be able to use the "band" button on the steering wheel to jump from AM to FM to SAT and then use the up and down arrows on the steering wheel to go up and down the presets within each radio band such as AM / FM / or SAT.

the selection of mixed or individual presets is early on in the radio setup if . Hope this helps.