For the cascade level granting to work out...
You need to boost/level two sets of toons, per link in the RAF chain.

So if your chain is:
A > B
A > C
A > D
A > E
You'd have to level two toons on B, for the granted levels to add up to (almost, you'd need to be boosting a level 2, not a level 1) a full toon on A.

If your chain is:
A > B > C
You need to level four toons on C, for those cascading levels (C grants to B, and B grants to A purely by merit of the levels received from C) to add up to a full toon.

If your chain is:
A > B > C > D > E
I don't especially like this one...
You need to boost/level 16 toons on E, for the cascading to work properly (with a limit of 10 or 11 toons on an account)...