I dont think that's right.
Here's what I have setup to test:
Preset 1: No foot switches, no instant commands
Preset 2: Foot switch to control amp drive channel. No instant Commands
Preset 3: Foot switch to control amp drive channel, instant command for drive channel
Preset 4: No foot switches, Instant command for drive channel.
Switching to 1 leaves the channel selected unchanged. So if it was on, it'll be on, if it was off, it'll be off.
Switching to 2 changes the channel to whatever 2 has configured (eg if the foot switch was on when the patch was saved it'll be on)
Switching to 3 is the same as preset 2, it's whatever the foot switch's state. The instant command doesnt seem to have any effect.
Switching to 4 turns on the drive channel.
So if I want to turn off a channel when a preset is selected, then I'll have to map it to a footswitch, then turn off the footswitch then save it. So every patch would have to have 2 footswitches on it, one for drive, one for boost.
If i want to turn on a channel when a preset is selected, then I have to map it to the instant command. No footswitch mapping required.
It sounds to me like there's a missing feature in the software: An instant command to turn off a channel.