Riser type slot type commutator VS hook type commutator

For auxiliary motors, fuel pump motors, starter motors, E-motors/Alternators, household appliance motors, industrial motors and power tool motors.

Commutator work with carbon brush and for motor winding and welding, the double flyer armature winding, in theory, hook type commutator armature winding is easier than raiser type commutator rotor winding.

But why some plant use raiser type groove type crown slot type step type commutation used on DC motor?

In some product such as power tool motor, as the competition is there, so the margin for each product is small, so each process of motor manufacturing, if there is some part can save cost or reduce cost, it is very important for the motor manufacturing plant, and as hook type cost higher than slot type step type commutator, in some condition slot type commutator is welcomed by motor plant.