An inherent design flaw in the Deathadder.
You have to set up a seperate profile and assign the sensitivity.
Generally to the scroll wheel the only problem is you'll have no indication of what the sensitivity is that you are running on the fly.
You can assign 3 to the wheel and have to get use to it.
I love my Deathadder but my MX-518 is much better it in that department.