Thank you for your detailed response and for the great links! Since I first posted that on the 21st, I've still been researching like crazy (Internet and phone) and I'm convinced my problem isn't grubs. I'm pretty sure it's too much rain. The areas with the most yellow spots are where the new grass is. Cornell Cooperative Extension's thought.....that the grass isn't as well established, roots not as deep, as the old lawn (haven't needed to go deep with all the rain), and then when it gets hot at all, it turns yellow or brown, esp. near hardscape areas. Plus not much sun to green up.
I saw so few Japanese Beetles this year and have never had a grub problem. I think I was just being paranoid.
As far as the 9 lbs. per square inch, it says it on the bag under the section for grubs. Fortunately, I didn't see it at first and only put it down at the 2 lb. rate. Whew! But with all my research I learned all about milky spore and that's what my plan is the first sign of grubs. Still learning and I so appreciate the advice!