I can help you answer this possibly.
When i did RAF i would level up with my friend and we would just get all the way to 60 and i believe 60 stops the RAF boost in retail.
So If you level up without your friend it saves the exp you have and you can grant you friend levels up to 30 in total, if it's the same on this server.
So! You can get to 60 and your friend is still 35 right, you can grant them basically 15 more levels, you get "1 grant" per 2 levels you do. So if your friend levels up once and you level up once, that's "1 level". sooo...30 grants in total, you would need 2 level 60s that have done this to give your friend 60 levels in total. So that means...you need 2 levels 60s, they need 1 level 60 to help you in the first place level up or you can just add them on the RAF and grind your way solo to 60 to obtain 30 levels and then repeat that way...i hope i type this right.
Either way good luck yo!
it does work, just play with it, it's not bugged or exploiting, you just need to understand the RAF system to make the most out of grant a level. Wait till your friend is at like 95% exp then grant him a level, then they will start out around 90% of the next level already, once they level, they grant you and you can hop up 2 levels a time. 🙂