ORIGINAL: Hornfan
You get an increase in the 3.5 score because the better 2.5 make it 3.5.
Instead of only the 2.5 four points making it to 3.5 and scoring 100; the eight point 2.5 makes it 3.5 and scores 120.
OK, but with the antler restrictions, the better 8 point 2.5 YO would more than likely be "legal" to shoot. The lesser quality 4 point 2.5 YO will have a much better chance of making it to be 3.5.
Antler restrictions alone will not necessarily make for better 3.5 YO deer.