I checked the maintenance manual, JetAGoblin, and what you stated is absolutely correct: "the transfer valves will close at the next refuelling" means that it is not the refuelling switch or similar that closes the valves, but the low level sensors, when they become wet again.
And I'd like to add something interesting: that is not true that there are absolutely no limitations to refuelling on batteries only: the AMM says that it won't be possible to get the maximum capacity.
In other words, when the high level sensors in the inners sense fuel, the refuelling stops.
But the inners are empty...
Here is a good reason for adding this point in the FCOM (there's nothing in the FCOM about it).
Cheers,
LEM