WM6.5 To Android data usage comparison

I am going to switch to android from WM6.5 (Att Tilt 2 to Atrix). Are the data requirements similar with the two OSs?

Can I expect the usage to stay the same if all my surfing habits stay constant. I was just wondering if I will be able to switch from the unlimited to 200mb/month plan. My usage for the past year has been:
Feb 2010: 123.7MB
Mar 2010: 85.9MB
Apr 2010: 153.4MB
May 2010: 158.1MB
June 2010: 204.5MB
July 2010: 259.9MB
Aug 2010: 147.9MB
Sep 2010: 199.1MB
Oct 2010: 195MB
Nov 2010: 209.9MB
Dec 2010: 105.3MB
Jan 2011: 140MB
I figured if I turn on WIFI when im at home/work i could manage to cut the usage down and same $15/month.

Thanks in Advance