Really? Maybe that's a UK thing.
The range balls our courses use aren't always brand new, but they are standard golf balls. I notice no particular difference with my length from the range to the course.
.96 times a 1 average rounds to 1, for that matter .96 times a 5 average rounds to 5. The .96 has little to no affect on most HI calculations for scratch or lower HI's. That's why it's called a bonus for excellence, it's a slight penalty to high handicappers.