If every i.u. of gh used produces 5-7 mics of igf then why would 40mcg ed be a waste; or even 25mcgs?

25 mcg =4-5 i.u. of gh in comparison
40mcg=6-8 i.u. of gh. in comparison

seems like the breakdown makes sense to me...........maybe you can't "feel" it like you can when on 60 or 80 mics.....but it's still got to do good!??