This is true - at least in Chiang Mai. But that assistance is telling you to contact Star Visa, there 'partner' in Chiang Mai. And, for me, that help would be me driving further than I'd need to to get to immigration, then having to return the following day to pick up my passport. If I do it myself early one morning, it's all done there in minutes. Then, the next one, if required, can be done online.
They also assist you with other things, like obtaining a Certificate of Residence, and only charge a mere 3000 THB for this service... Maybe some people on a Thailand Privilege visa have more money than sense and are happy to throw money around. But I only bought mine out of necessity.
It certainly feels that way - to the point I'd rather ask anyone but them for advice.