Submit Buttons on the Left or the Right?

We have been puzzling over where to put the submit button, on the left or the right. In researching, we noticed that many sites put buttons on the bottom right in dialogue boxes, and on the bottom left in forms.

It makes sense: in a dialogue box it seems to denote finality, being in the endpoint of the window for left–right readers; in a form, the bottom right could be in a different position relative to the rest of the form if the window is resized.

It seems to be a convention, but I don't see anyone talking about this specific phenomenon in the following questions, nor the articles referenced therein:

Should the OK/Cancel buttons be aligned right or centered?

OK/Cancel on left/right?

http://www.lukew.com/resources/articles/psactions.asp

So, is this level of button position optimization worth it if it creates an inconsistency in button placement? Is this a good way to go?