No wrong buttons. I tried it about 5 or 6 times in different ways but could not get back from the South China Sea on a half tank.
I don't run 1/3 or 2/3 either. I run manually at 9 knots. !0 or more is far to fuel consuming for a Porpoise.
I'm guessing I had a leak that was never found or fixed by damage control.
I don't have an answer. I just started over with a new career and Sniper's mod.