When you're out of position, shouldn't the "latched" light change to "disconnect"? I wasn't totally full (unless I've forgotten how to properly read the fuel guage, which is entirely possible), but I'd taken a significant amount, which is at the very least a partial win for me.
Edit: Just had it when the boom was at green, so it's definitely a replacement for "transfer complete". It also shows that I'd forgotten how much fuel the A-10 holds, as the guages were just above the 4.