R value is what makes insulation work, not the sales pitch someone gave
you about houses heat 2-400 percent less with foam as you wronly state.
I foamed the exterior of my house with R 14.4 foam and R 100 in attic my
bills went down 25%. If you were correct I would be paying 400 % less.
And nobody knows if Icynene will deteriorate like UFFI. Still R 7.2
foamboard is your best bet. So is following code minimums..