Actually, relatively speaking, the amount of offense freed up by Forts for Elf is less than that of any other race because you're reducing a smaller number by the same %.
Example: Dwarf vs Elf 42 DPA goal
Assume 200% wages and MP cast ~1.129 DME mod
Elf: 42/6/1.129 = 6.2 DS/A
Dwarf: 42/5/1.129 = 7.4 DS/A
+20% bonus from forts = (1.076+.2)*1.05=1.34 DME mod
Elf: 42/6/1.34 = 5.22 DS/A EPA saved: 0.98
Dwarf: 42/5/1.34 = 6.27 DS/A EPA saved: 1.13