I can sympathize with your dilemma. Your doctor has one point of view, but what does your heart tell you?
Personally, I think ten hours without food for a 4.5 month old baby is an awfully long stretch, unless they do it naturally by sleeping through the night. How long do YOU go without food? Most of us eat every 3-6 hours, even as adults. Babies are digesting fast and growing fast.
With my own three, I preferred to FEED ON DEMAND -- as in, they eat when they are hungry, and they don't eat when they are not. In a country where we have such a problems with eating disorders, obesity, etc, this makes sense to me. The trick is not assuming that every whine or cry means they are *hungry*. Sometimes they are dirty, wet, cold, bored, lonely, or scared. As they get older, *they* will tell you when they don't need that extra feeding anymore.
Of course, many will disagree with me who have a different way of looking at it. But this approach makes sense to me, to show kids to eat when they are hungry and not on some arbitrary time table. Each body is different, our intake needs differ, our schedules differ, our appetites differ. I honestlyu wouldn't take away more feedings until they are eating solid food.
I know of no research that shows that making a child go hungry will help in the case of acid reflux. I'd check with a specialist.