Every immigration office, consulate and embassy has their own unique visa/extension requirements and pricing. For that reason I will be avoiding any extension requirement lottery and sticking to border bounces where I just show my original DTV approval pdf and get a new stamp. That'll also help me stay under 180 days in Thailand until I figure out the lay of the land re: the new taxation policies. 🙂 EDIT: Hey Mar Wan! Just realized it was you. 😀
I will do a quick in and out DTV reset before I will ever do a DTV extension. It's too risky for the reason mentioned: requirements are open to interpretation by local IO. Best to keep your already approved DTV for 5 years IMO and not extend, just leave and come back in.
Wife and I also had a great experience with the Vancouver consulate at the end of July. We had just been approved by them for Non-O visas based on retirement. Then the YT video came out of the interview with the immigration boss explaining all of (well most of) the DTV unknown's. The DTV sounded like a much better fit for us so we contacted the Vancouver embassy again. They told us that we could apply for the DTV and if we didn't get approved we could keep the Non-O's. If approved they'd just cancel our Non-O's. I immediately submitted an application (very similar to OP's) and 2 hours later was approved. 24 hours later wife was also approved as a dependent on mine. Very happy with the service in Vancouver.