Yes! (meaning yes, change the switch - It's OK to run it, just not the way I originally stated). If you are running the LC+ with the remote, that's effectively Command mode, just a new less featured flavor of command mode that didn't exist when the label was printed.
If you are running the LC+ truly conventional with varying the transformer voltage, you likely wouldn't have it set at 18 volts all the time, and then setting the switch to the Conventional position would be appropriate.
Since you are using 18 volts on the track continuous for your LC+ engine, leave the switch in the TMCC/DCS position.
I said the other way before because you stated conventional, which means varying voltage to the track to speed up or slow down your engine. As much as this new LC/LC+ may seem like a new flavor of "conventional", for these purposes, it's command.
-Dave
