You are not transiting you are changing flights and as such must go through Immigration and enter Thailand. Thailand Pass and all the requirements that are attached. New plan, because the existing one doesn't work.
I think to avoid the requirements of having the cash parked in a Thai bank for the yearly extension, you would need to leave Thailand on a re-entry permit, get another years insurance and get stamped back in for another year
here's one, recently returned from Australia, went to Samut Sakhon Immigration to lodge a new TM30 and was told it was not necessary because I haven't changed address.