Hi Savage25
Following my posting, I have visited THAI office in Singapore. According to the helpful reservation staff, she has informed me that it is still possible for me to enjoy all benefits of my KF Gold and still accrue mileage to my ROP account (which is at Member level only). She said that so long as my KF gold status is valid, they will honour all benefits accorded to *A Gold member.
Not too sure how true this is, but it does sound logical... Maybe you would like to share with us if you have such experiences while experimenting with it.