I've run the same 20 pound trend, until I blipped out of plus sizes into 18's. You know, 18W, 18, 16W, 16, 14W, 14 just messes everything up! Once out of 16W I've gone down a size every 10 pounds, depending on manufacturer/vanity sizing.
Right now at 205 I'm wearing 16's, some 14W's, and almost able to get into 14's. They button/zip but they are too tight to wear out of the dressing room!
267: Highest known weight
242.5: Weight on dd's 1st birthday
213: Weight on day I delivered dd (Whooshed past on 7/6/10)
200: Weight on day I went home from hospital after delivering dd (MET!! 1/24/11)
180: Lowest weight ever as an adult
170: Initial goal weight (subject to change)