Diagonal Weapon Reach question

[alex1g]

Since we're playing 3.5 the diagonal movement distance is 5, 7.5, 5, 7.5 feet increments, but does that apply to weapon reach. I could have sworn that diagonal weapon reach was based on a 5, 5, 5, 5 feet distance increments. So the 7.5 feet does not apply to the reach weapon. What say you.

[fallensavior]

Small and medium creatures with reach weapons are an exception to the "every 2nd diagonal counts as 2" rule. (PHB 137)

[Khedrac]

Small and medium creatures with reach weapons are an exception to the "every 2nd diagonal counts as 2" rule. (PHB 137)

Beyond that first ring, diagonal distances are measured normally.
The logic appears to be to ensure that no creature with reach can be approached without passing through a threatened square (once you go large the threat range is 10' deep for a reach weapon so the problem does not arise.