Also, keep in mind that it depends on what editors you get that day as well. Even though AC has guidelines on what they will and won't accept, many times it comes down to a picky editor. I've layed out in the "made $30" thread how I handle rejections in case you haven't read it. 9 times out of 10 if you tweak them and let some time pass before resubmitting, you will have it accepted when it's reviewed by a different editor.
I've had articles get an upfront offer of say $3, and decline their offer. I'll let the article sit for a week and rework it a little, then get $6+ when it's reviewed by someone else.
AC editors see things very differently sometimes.