Opinions on windage screen

This is true to a point. The power gained doesn’t add up in that fashion but it does add up. It is not a simple 1 + 1 + 1 + 1 + 1 = 5. Sometimes it equal 3, sometimes it equals 6.
Truly correct in that is all about oil control. Controlling the oil needs to be done. Performance engine to race engine, it shows good results. Thus making more power. Lack of control, less power.
Thus losing less power.
And dynos don't simulate the g force and slosh.
Without individual testing AND in a broad range of circumstances...its hoping at best, to each his own...and application.