Why do the number of forms controls different between FAE and the Firefox Accessibility Extension?
The Firefox Accessibility Extension gives you a list of all the form controls at one time. FAE only reports on the number of form controls found that apply to that rule. For example, form controls like text box, radio button and checkbox need a label element associated with them, but the submit button does not. So the rules that apply to label would only count the controls that need a label and not count controls like the submit button.