I’m not specifically familiar with the new “Air-X” machines, but the old ones have a very good reputation. They’ve made several improvements over the years, and apparently continue the practice.
A Pulse Width Modulation controller varies the charging current
gradually from 0 - 100%, much like a lighting
dimmer does. Shunt style regulators merely turn the output on or off, like a ordinary light switch.
The PWM control works more like a “smart” multi-stage battery charger
, and can incorporate other features that may increase the maximum energy transfer and improve battery life.
I’d be inclined to believe the catalogue claims you quoted (I’m normally a skeptic, so this doesn’t come easily to me) . Air-X would be among the first machines I’d consider for myself.