In case it helps anyone, I went on a mission and I confirmed the ASUS manual is wrong. I checked for continuity using a multi-meter and indeed the physical pin layout of the W_Pump pin header is the same for any of the fan headers. I placed my H110 3 pin pump wire to W_pump header and my cooler fans to CPU and OPT headers. In both Bios and HWINFO pump rpm can be seen. If you can, prior to making the swap of plug locations, first enter the bios and under the "monitor" table enable the water pump monitoring function. This by default is disabled. This also allows you to set or modify the speed of the pump based on load, however it is recommended to keep this at 100% (about 1500rpm for a H110) at all times. I do not believe there is a alarm in the event of a pump failure, unlike that what occurs with the CPU header, which is why some people prefer to use that for pumps. However a easy workaround to this is to use HWINFO to run a action to shutdown in event pump speed falls below a certain level. Refer to the HWINFO forum for more info on this.
I trust this helps people out