You can get a 5th on A through gifting levels when you use the A-B-C-D-E approach.

So, in one case you have to level up a toon to L30 or L31 on account A and gift the 29 levels from B (which you get once you level to 60). If you level two or more toons to L60 on account B you have enough levels to gift a L1 to L60.

Also, keep in mind levels gifted from account C to account B also result in more levels to gift on account B. For example, if you have a L30 toon on account B and you gift 30 levels from account C, account B will now have 29 (or 30??) to gift from that process (from both leveling + gifted levels). Just pointing this out since I hadn't realized gifted levels also grant gifted levels when I was doing RAF.

Account E is the one that actually loses out.