I'm sorry. I forget exactly how the Journeyman measures chainstay angle. Below is a screen shot of a few chainstay related angles. I've highlighted to angles in the Frame tab of the Dimensions dialog box. Chain stay angle (actual) is the actual angle of the chainstay itself relative to horizontal. Meanwhile Chain stay angle (Rear axle to BB) is the angle of an imaginary line running from the rear axle to the BB. These two dimensions may or may not be the same. It will depend on how the chainstays attach to the dropout. The attachment point may not be in line with that line running from the Rear axle to the BB.

I've also shown the Seat tube - chain stay interior angle which you'll find in the Jig setup tab.