I think this was meant to include the other John who responded to you. I think what he is saying though, if you keep telling the embassy that you will be there for less than six months, they will keep giving you a tourist visa instead of DTV.
It doesn’t hurt to ask for an earlier interview. However, I suspect there has to be a reason why your interview is in two weeks (fully booked up with interviews until then, etc.). The Vientiane embassy’s webpage says one should expect it to take 10-15 business days
There were two holidays during that timeframe, so actually 15 business days. Furthermore, the Thai PM’s visit probably caused consular services to be closed for those 3 days she was in country. Unfortunate time to apply.