You are not renewing your Visa, you will be applying for a 12 month Extension of Stay and you have to apply for it before your current entry stamp runs out.
The local Immigration Office does not automatically use every visit as a 90 Day Report e.g. purchasing a re-entry permit and not even, as you stated, when you renew your Extension of Stay (not Visa) necessarily. If/when they do they put a new 90 Day Report slip in your passport.
You go to Immigration on the 25th to cancel you current Extension of Stay (I assume, not a Visa) and apply for an Extension of Stay (TM7), pay 1900B and get an "Extension denied, 7 days to leave Thailand" stamped in your passport