I’m talking about three G.91 models.
G.91 pre-serie in Naval RB:
The G.91 pre-serie was moved to 9.3 in Naval with all other G.91 under the pretense that all G.91 get AS Nords. However, the G.91 pre-serie gets at best 500lb bombs. I would really like to bring my G.91 pre-serie into my 8.3 Naval lineup for CAP, but it’s not possible right now.
G.91 R/1 in Air RB:
Compared to other G.91s at 8.7, the G.91Y has no advantage. It gets two AA-Nords, but the R/4 can bring four of either the Nords or AIM-9Bs. The G.91 R/3 gets significantly better guns (DEFAs, like found on the Y/YS). It also must be mentioned that when using Nords, the plane is limited to just two .50 cals. It is only very slightly better than the G.91 pre-serie in flight performance, with a roughly 3% increase in engine power. There are plenty of examples (Including with the G.91Y/YS) where the addition of AIM-9Bs-esque missiles increase the BR of the same vehicle without (MiG-17AS, Dutch Hunter F.6, and the F-104C is a higher BR for just going from 2 to 4 missiles). The MB.452 IIA and IIC is also an example of the guns raising the BR, and that’s from 20mm to 30mm.
G.91YS in Air RB:
This one only makes sense if the G.91 is not moved down. If the G.91 R/4 can stay at the same BR in Air RB with 4 AIM-9Bs as the G.91 R/1 with none, than the G.91YS which only has two AIM-9Bs over the G.91Y should not be higher. This is especially considering that the G.91YS can see the MiG-21SMT and A-10A in a full up tier. The ballistic computer is the only other advantage it has, which is near-useless in Air RB (at least at 9.3 as a stand-out feature). The aircraft is identical otherwise.
For the last two, I think these a remnants of the time where BRs were shared between all realistic modes, as yes, the two aircraft make sense to be at that BR in ground realistic. I think Gaijin just probably looked over them when making the BR split change.