I have full UK. licences for both motorbike and car. Plus my international driving permit. When I first came here I assumed I was driving legally on the above until I was told different. You can only drive/ride on your home country licence for up to three months, after which you need to apply for a Thai licence, (very easy). Apparently the police may accept your home country licence, but insurance companies will certainly not. Any claim you make will be rejected. Not worth the risk.
I think what you’re referring to, and I’m no expert in these matters, is that we were exempt from doing our ninety day report during the visa amnesty period to avoid large crowds at immigration. However, I think it was a date sometime in late August we had to update our reports by. I chose to keep my reports going by doing them online, so I wouldn’t have to rush and queue at immigration when the amnesty ceased. So I didn’t see this as a waste of time. Hope this makes sense.