Filling the expansion space?

[Fazafou]

I used to put mine on the centre stand and fill it up slowly as it gets to the top, wait till the level falls and put another squirt in, repeat the last two steps until you get bored. Takes ages to do.

Yeah that's pretty much what I do now, but lose the will waiting for it.

I guess it would probably only save about 5 miles or so, maybe not worth the agro messing about.