@Josh *********
you are highly confused. You have nothing to do with filling out any TM30 form. You fill out your extension form, and that has nothing to do with your landlord and the fact that you move. The only thing immigration is concerned with is that your address that you list on the form matches the current TM30 they have on file at that very moment. They do not care if you move after you apply and the extension is approved. The extension days are added on to your current stamp, so you do not lose any vacation days by applying early. You are trying to overthink something you made up. It has no reference to your extension at all.