I have not seen Dr Mahesh or Dr Sheila before, this is what I understand: before pregnancy, they do extensive blood test to determine the cause of the miscarriage. The causes varies widely from vitamin deficiency to immunology related issues to sticky blood (I think sticky blood is most common). Once tested BFP, they continue to monitor closely. I'm not sure if Dr Loh or Dr Roland does such blood test to help determine the cause of miscarriage, since they are IVF specialist after all.
For me, I've just failed my 4th FET at KKH. So, I've booked an appointment to see Dr Roland for the first time at the end of the month. My first FET was bfp but miscarriage at week 5, subsequent FETs all bfn. I don't know if he can help me at all, but I want to see him for second opinion. Not keen to see Dr SF Loh because of the inconsistent experience shared by different people.
If I had 2 miscarriages, I would go to Dr Sheila, find out what's wrong with me. Then go back to KKH for the usual IVF. Once bfp, I would go back to Dr Sheila. However, they see patient with recurring miscarriage, which means they probably wouldn't entertain me since I only had one.
This is just to share my personal plan and preference.