I've got extensions of stay/work permit for many years on the trot, and it's always been extend the visa first and then extend the work permit. I suppose it depends on the immigration office/labour office in each area. I'm in Ubon.
What it needs now is for the MOL to make an announcement clarifying the matter in both Thai and English. In fact, they should have done that in the first place, not allow some website to announce the matter and leave everyone confused. However, we should probably not hold our combined breaths waiting for the MOL to do anything, I fear.
I think you are totally correct. I have a WP that enables me to work as a volunteer for a government agency (NFE). I do not teach but am able to act as a speaker at teacher training, work on teaching materials, etc. As far as I can make out, this 'new' approach to WPs will allow me to work in other NFE offices without having to make any alterations to my WP provided the work I do is still the same as described in the WP itself.
I would believe all this a lot more if I could find the information in Thai. I need to see that information in Thai before I fully believe what thephuketnews.com is saying. Right now, all we have to go on is a report in an online 'newspaper'.