stat-range -2 -> +3...why?

Vincent, you decided to make the game work by rolling 2d+<thing> where <thing> is quite often a stat that ranges from -2 to +3.  Why that instead of 0-5 and slide the 7-9 and 10+ up a couple of notches? 

Was there something specific?  Did you like the way those numbers interfaced with other numbers that are a 0-n scale or something?

Oh sure. It's a small sleight of hand.

Without ever saying so, it presents 0 as the baseline stat, which makes +1 seem like an above-baseline stat, even though the average stat is +1. If it were 0-5, I couldn't get the same effect; I'd have to just assert that 2 is the baseline, against the evident fact that the average is 3.