Increment Range of Upsized or Downsized Bows?

[Thistleknot]

It's fairly obvious how to upsize or downsize a bow's damage, but what about the range increment?

It looks like the increment changes by 40 ft up or down just looking at the difference between the composite longbow and composite shortbow, but this doesn't always seem to hold true.

If this simple linear progression held true, then the Storm Giant's Gargantuan Composite Longbow should have a range increment of 190 ft rather than 180 feet listed.

Does anyone have any thoughts or answers on this question? Any thoughts or comments would be greatly appreciated.

 

[CRGreathouse]

I'd change it by 45 feet upward, 35 feet downward. How well would that work?

 

[Spatula]

Savage Species says to change the increment by + or - 25% for each size increase/decrase.

 

[Thistleknot]

Thanks for the suggestions!

I really appreciate it! =)