I misunderstood. I thought you were draining the tank.
As far as extra propane use, the system is running the generator at no load for probably a minute before the gas in the piping is used up. Hardly any extra consumption compared to the fridge and so on. I am not draining the tank.
It is a fairly common procedure. This is the first of the many google hits I just had. Not everyone on this Minn fishing forum is correct about what they are saying regarding the propane phases, but you get the picture.
https://fishingminnesota.com/forums/topic/159415-oil-in-a-propane-line/#comment-1400404