When we update here in CM (which may be the same procedure elsewhere), all you do is hand them your passport (with the TM30 Notice of Receipt stapled in the back, much like a 90-day Notice of Receipt), they check you out on their computer, and then they just put another date stamp on your TM30 Notice of Receipt (or print you out a new one if it's too ragged and then date-stamp that). When they are checking you out on their computer, they can see the TM30 filings that were done by others (usually hotels) when you've stayed elsewhere in Thailand. In my case, they don't even comment about it (i.e., the officers I've run into don't care about updating when you're only gone within country). I really doubt if you'll run into any issues ....but god/buddha only knows.
There is a lot of frustration up here in Chiangmai about how CM Immigration is working (well, not working). Our expats club had a few Immigration officers give a presentation at a meeting in October of 2015 and the officers used a few graphs showing how many items (annual extensions, 90-day reports, etc.) that Chiangmai was handling every year compared to Chiangrai (CM, as you might guess, did 3-5 times as many). When they were asked about how many immigration officers Chiangrai had compared to Chiangmai, the unbelievable answer was that Chiangrai had more immigration officers. That, in large part (besides the different rules by different officers), lies our problem.
Geez, they know our address from our annual extensions, our 90-day reports, and even from our TM6 departure cards. Besides being a money maker, the TM30 routine is just an additional waste of time and involves immigration officers that could be doing more important things.
Then there is the TM28 joke....the TM28 being the form that a foreigner self-reports his/her address. This little baby is covered by the same statute that deals with the TM30. Yet, based on almost all reports from people who've tried to file those at CM Immigration, those are handed back and the people are told that Immigration doesn't want them or even know what to do with them. That, too, could change (hmmm....wonder what the fine will be for not filing one of those?).