New Deluxe PWM and 3pin Fan Headers for Sabertooth Z170

[BonzaiDuck]

I may have cheaped out on choice of a motherboard. I'd been looking at the Sabertooth Z170 Mark 1 for many months. Then I hatched a plan in which my mobo-ducting was more elegant, simpler and effective. So I chose the Sabertooth Z170 S. I think that the two models have a identical specs on the essential features. The S board lacks the mainboard duct plate and doesn't come with a 40mm fan to fit behind the ATX I/O panel to cool the VRMs between the panel and processor. The S has a duct with a 3-inch plate covering a place to insert the fan. I later find that both the Sabertooth boards are 12-phase power design, while the Maximus and Deluxe boards are 16-phase -- but the S board vies for 2nd through 4th place among those and other boards -- very close to the best Maximus. But I want to ask about fan-headers.

There are more than enough fan headers. CPU_FAN, CPU_FAN_OPT -- I'm familiar with. The ASST_FAN and EXT_FAN ports may be voltage-controlled as opposed to PWM -- I can't say. There must be four CHA_FAN[N] ports. Next to the CPU_FAN/-OPT ports, there is a PUMP port, which would work with a waterpump.

Is there any reason that this can't simply be used for a PWM fan or a PWM hub? Or is it just that they provide an extra port that can be controlled with its own %/temp curve, and call it PUMP because it's available for a pump? Would not the tach wire pinout work in the same way, and report fan RPM as well as it would show pump rpm?

Someone please enlighten me.