Turtle, insulation needs vary upon locality-zone. You pay to heat or
cool and more attic insulation helps. Many areas have heating as the
major cost not cooling, but I always find nightime humidities to high
during cooling season to open windows, although I agree in theory wth
you as I noticed what you mention, but the winter and overall savings up
north here negate what you experiance in your warmer locality. Uping R
even cut my summer cooling bills as heat is not let in the attic. Ten
feet of it you say, that would be upwards of R 420, kind of stupid for
you to say Ten Feet. Facts and proof are out there that codes are
insuficient minimums, there are guidlines that work to get optimal
values. You don`t live where your new heating bills may be up hundreds a
month or where a 90% furnace is not as good as a 94.5%. and a 80%
efficiency is a joke.