I think it depends on the blood glucose reading. When you went to your gynae initially, the reading (it was a single reading) could have been borderline high hence the advice that was given.
When you went to KKH later on, the reading could have been extremely high/clear cut in the diabetic range. Hence, they gave you medicine.
Your gynae then said to continue it because now your gynae knows that your reading has gone up to diabetic levels, and since you’re following up in the diabetic clinic in KKH, they are monitoring regularly and are in a better position to adjust your medications or see if you still need to continue with them.
Rather than it being contradicting advice, I think it’s actually complementary management between the 2 places, and I’m glad you had that visit to KKH and got the high glucose level picked up so that you can keep it good during your pregnancy for the safety of your baby. Hope all goes well with you ❤️