Congratulations flame, you've now experienced logitech.
First two wheels were faulty, third one broke taking the plastic off (out of the box), Fourth one worked. =D They are durable products, But the problems coming out of the box is a pain.
If you bought it off ebay. etc. it *may* be a older generation of G27, you'll want the newer ones.
Honestly, it may be your centering disk may be off if it's 20 degrees less.
I'm using 720, I havn't noticed it, There is soft locks on FFB, so you don't break the thing, If you set it to 100 degrees, you can crank it (Don't do this to much.) all the way up to 900 and let it spin back (FFB should make it spin softly back)
Deadzones could be wonky, But in the end, just phone up logitech with a laundry list of problems, it'll fix eventually. (however many painstaking months it takes logitech to pick up the phone, however.)