Clutch plates "missing" one inner spline tooth

The DR clutch plate kit I am installing in my GL150 from 1962 has one tooth left out in the inner splines of the steel plates.

This is not the case of the stock clutch, but I think I have seen it in PX125 steel clutch plates.

How should one place these cut outs in the clutch basket? All cut outs straight above each other, or in three different directions?
What is the purpose of these cut outs, is it to give space for more oil to enter and flow througt the clutch?

All straight above each others... that's it...