.... Oh, I forgot.... there also will be a Control Panel Programs and Features entry entitled TI USB 3.0 Host Controller Driver and mine is version 1.16.3
Check in that Control Panel.... that might be a place someone accidentally got to and uninstalled from with good intentions (but bad outcome).
For what it is worth, this same installer package is what I use when installing the HP "2x2" PCIe USB3 TI based card, which I have posted about here in the past. If doing that remember to always properly power up the card with its supplemental power cable before loading drivers. That way the the installer can see all of the card's hardware components during the install process. Otherwise you'll end up with a mishmash. That issue is not present for the on-motherboard TI USB3 chipset.... it gets its power in the Z620 directly from the motherboard it is soldered into.