mppt vs pwm

Salvo wrote:
Pretty much all modern controllers use high frequency. The higher the frequency, the smaller the magnetics become. Costs go down.

BFL13 wrote:

There is high frequency PWM and "low frequency" PWM. The "PWM" 12v controller uses low frequency PWM to "control" when it is stopping voltage from going any higher after it starts controlling.

I suppose the "MPPT" controller uses high frequency PWM to keep at the MPP during Bulk, and "low frequency" PWM during Absorb and Float same as a "PWM" controller does---but I don't know.

BFL, are you perhaps saying both controllers use a highER frequency during bulk, and a lowER frequency during abs/float?