my personal opinion, if seeing a private gynae at 28weeks, if i were u, i will just carry on seeing the gynae with subsidise rates. you are just left with a few weeks more Mummy.
Be it private or subsidise gynae, you can ask them any questions. The only differences is the gynae is not fixed for each and every time you come for ur checkups compared to private gynae. But at 28weeks, you are already in ur 3rd trimester.