The other thing the report isn't saying is that those numbers improve a lot if you have power transmission or other forms of power generation (say wind). They're calculating things as if you're a datacenter in a single location trying to yourself without any grid connection.

A small amount of other power generation whose output isn't correlated with the sun overhead should do a lot to make the last few percent (which come up when there's many cloudy days in a row) cheaper.

Solar's just knocking it out of the park at this point. Building out anything else new (as in you haven't already started) doesn't really make sense.