Pentair Challenger Diffuser Designs. Why different?

[Thinkly]

I have a 3/4 hp Pentair Challenger. I am curious why my diffuser has a different design than most that I see, including on the parts diagram at Pentair.

Mine looks like this.



Instead of completely round like seen at the link below. Does anyone know what is the purpose of the different designs?

Amazon.com : Pentair 355270 Diffuser Replacement Challenger High Pressure Swimming Pool Inground Pump : Outdoor Spas : Patio, Lawn Garden

 

[mas985]

I think the internal hydraulic designs are usually similar (vane placement and spacing).The picture above shows the opposite side of the vanes so it really has no impact on the hydraulics and is used for mounting only. There are many different designs and some diffusers are inserted into the pump inlet while other directly attach to the pump basket.

But I think that diffuser is for the Challenger high flow pump and not the high pressure pump.