Lithium Ion batteries do not have a "memory" like the old lead acid ones did. Charging at different states of discharge has no effect on lithium ion used in your e-cig. Although it seems to be a good practice to give your e-cig a full 8 hour charge as often as possible.
Some passthrough devices with a battery in them would fry the battery if they were being used as a passthrough (ie. charging and vaping at the same time). I have no idea if that was the result of crappy electronics, or lithium batteries don't like being charged and loaded at the same time. I can't speak about the Revolution V2.1 as I've never used that device, so the advice in regards to using it as a passthrough may or may not apply.