A few pilots are having issues with AUX TANK HEAVY messages. This is totally understandable as (A) we didn't tell you how to work the refuelling system and (B) Good grief - never let a pilot near a refuelling truck!
The docs will be reviewed to see if something better can be written, in the mean time... Refuelling - Easy Method
Tell the fueller how much fuel you want.
He's going to say "I'll start up the pumps".
Wait for him to go downstairs, then only switch the L WING and R