Making pattern larger

How do you calulate measurements to make pattern larger

Example: 16 st to 4 inches = 4 st = 1 inch
pattern size is 35 37 39 41 cast on 77 back increase by one
cast on 45 for right and left fronts.

I want to make a size 48 so I need to increase by 8 inch to get a size 48 bust.

I was going to add 4 stitches (5 times) to each measurement (cast on stitches)

77 plus 4, 5 times would be 98 st cast on for back and
45 plus 4, 5 times would be 65 st for each front

Is this correct

At a LYS a lady told me to increase size by looking at there sizes given and see how many sts they used to make each size bigger and use those numbers 35 37 39 41 so 2sts to make each size larger .Just keep adding the number to all of the numbers given though out the pattern. Haven’t tried this but makes sence to me :shrug: