Master's courses with 'exception' status, and repayment income thresholds...

Hi there, I understand that for most master's degrees, the yearly income threshold to repay a loan is £21,000.
However I'm looking at studying an occupational therapy or speech and language therapy MSc, both of which should be 'exception courses' meaning that the conditions for repayment should be those of an undergraduate degree (NOT those of a master's), ie the yearly income threshold should be £25,000. I just wanted to confirm that this is the case as I can't find it in writing anywhere.
Thank you!