I have mapped the IR hex outputs for all 256 EFCs for remotes from five different vendors. (They all use the same map.)

1. Goldstar, vendor #04FB
2. Vizio?, vendor #609F
3. Toshiba, vendor #45BA
4. Magnavox, vendor #8722
5. Western Digital, vendor #8479

I have even developed an algorithm for converting IR hex numbers to EFCs.
They all use their IR#s differently, but the same EFC produces the same IR#.

#1-3 are in the 6122 format.
#4-5 are in the 6122A format.

EFC Map.pdf

I found a device where my given map is inverted.
When my map is correct, EFC 00000 produces IR hex 9D (OBC 157).
When the inverted map is correct, EFC 00000 produces IR hex 62 (OBC 98).

You can convert MY EFC to its inverted value using the following formula:
AltEFC = (199 - MY EFC) mod 256

In Excel, AltEFC = MOD(199 - MY EFC, 256)

The easier solution (for some) would be to bit-flip the IR hex# (FF - IR#) before using my map.
Using the above numbers, FF - 9D = 62.
(All math is in hex.)