I'm making a hem in a sheet metal part. When I edit the hem width to leave a .25" relief, I end up with a relief that's actually .254". I can see the edge width sketch endpoint in the correct location, but the hem ends in a different location. I've tried editing the relief to a tear, but that doesn't fix it.

The first picture is the corner of a sample part with the hem. The second picture is the hem edge sketch visible.

Any ideas why the feature is created inconsistent with the sketch?