Denny, I haven't read all the responses so I don't know if this was brought up.
Up until yesterday, I've been using a brewing calculator for my strike and sparge water calculations. I usually ended up with about 8 gallons of preboil wort with my method which consisted of 3-4 gallons of strike water and 5-6 gallons of sparge water, depending on recipe. I would never try and split strike and sparge water 50/50 (like your method). Usually, my way had great efficiencies but my gravity would be a few points low. Your way, yesterday, gave me a more accurate OG. Did that make the difference?