Having lived in Singapore for quite a while, fully agree that you must do
exactly what it says on the form. No more, no less.
You could change your name to David Robert. My father-in-law has those first names and when he used to come and see us he often got an upgrade because they thought the DR meant doctor.
He was always a little concerned that he would be expected to administer emergency surgery to a dying pax, but he was never called upon.