I had five accounts going with game cards.
ABCDE.

I have RAF linked two chains:
A > F and B > G.

I am using E to boost ABFG.

My subscriptions ran out on ABCDE.
The free month was about to expire on FG, in three days... but they were still active.
So I bought three game cards, and used them on EFG.

Because FG have paid for a month, their referring accounts AB each receive a month free (and because of the 2nd month, AB each get the RAF rocket too).
E gets two months from the game card, which is normal.