Yep, that's accurate but can also be misleading. I'm able to break one of the valves in a two-valve tank without losing any liquid, as long as I don't touch the other one until I've reformed the tank. I'm guessing the way this works is that when the tank is broken, the liquid gets evenly split and assigned to valves excluding the one that was just broken. For all I know though, it might depend on the order in which blocks are updated, which can be unpredictable - maybe breaking the other valve would have caused me to lose half the liquid. I'll have to do some more extensive testing to be sure.