I've never had to buy a front sight, so I was just guessing how it was measured that made sense. What about sights that don't use a dovetail, and screw down? You would have to measure those from the top of the barrel. It seems they would make it the same for all styles of sights.

The OP measured from the flat on the barrel which would make it shorter than from the bottom of the dovetail. Yet, TOW didn't have a taller sight. Which means they didn't even have a sight as tall as the stock sight. Let alone a taller one.

Leaves me scratching my head.