Dtv soft power.

Has anyone gotten their dtv approved for 1 course but then decided to change to another one? I initially signed up for muay thai 9 months but hurt my self and the doctor advised to stop for at least 6 months and then review. I'm thinking of changing over to an approved cooking class instead, but not sure if that's allowed

I am considering applying for DTV for medical visa. I have a spine condition and have already seen a doctor in Bangkok who gave me a medical certificate with diagnosis and treatment plan however the certificate says treatment (being medical physical therapy at a hospital) for 6 weeks. However since he only wrote it for 6 weeks would it not be approved? Should I ask for a longer treatment plan?