I found this if anyone is interested:
BYO - Buffers: Advanced Brewing
This is the bottom line from this author:
"The pH of your brewing liquor does not determine your mash pH. In fact, almost all brewing waters will yield a mash pH in the low to mid 5 range, regardless of water pH. For this reason, adjusting your water pH is of little use (unless you know from experience that adjusting your water to a certain pH yields a given pH in the mash). Likewise, the pH of your sparge water does not determine the pH of the wort you collect. Even near the end of wort collection, the weak wort in your grain bed is more heavily buffered than your water.
So what about this summary? I am curious from the water educated guys here if that is correct. If this is true than it changes things for many.