Looks like the 14.5 pressure angle to me.

Strength of gear teeth is calculated using the Lewis factor. https://www.engineersedge.com/gears/lewis-factor.htm Basically a cantilever beam calculation. A fatter tooth will be stronger. 20 degree pressure angle gives a fatter tooth compared to 14.5.
20 degree will also have greater force pushing the gears apart which is not an issue in this case.