Depending on using AVS709, DVE or my DPG1000, I could make my Samsung and Panasonic get 3 different gamma results. The DPG windows are just like your 1% windows, so IMO they give an accurate read. The 10% windows like the Accupel/GCD will sometimes barely kick in problems at 70-100 stimulus on a plasma, and the AVS disc will most definitely kick in problems because of window size.
The best result for 10pt gamma on my D7000 was with the 1% patterns on the DPG, IMO, so I will always keep it around for that use. It's just clunky, so it's nice to have a test disc now with Accupel sized patterns as well as 1%, maybe I dont have to drag it out from now on , at least until I buy a 5000. Im just undecided if I really need the beast or not.