WinDescent, Positive or Negative Value?

[lettersfromswe]

I just read here:

https://glyphsapp.com/tutorials/vertical-metrics

That the WinDescent should be a positive value, and not negative like the other.

Is this really true or a typo?

[composerjk]

Yes, usWinDescent is a positive number. Per: https://www.microsoft.com/typography/otspec/os2.htm#wd
and also see:
http://www.typophile.com/node/13081

[mekkablue (Rainer Erich Scheichelbauer)]

Don’t worry. If you enter a negative value, it is automatically corrected.

[lettersfromswe]

Ah, I love you guys!!!