if it helps, IME with loading VGC on RB:
1 i say i would like to load 400 onto RB with 2 debit cards
2. customer service asks how much on 1st debit, i say 200
3. she inputs that into machine, i swipe 1st debit
repeat steps 2 and 3 for 2nd debit card
once, the receipt was for 400 and another time i got 2 receipts for 200 each, depends on how the cashier does it