"They are still short on their harvested salt production by over...

"They are still short on their harvested salt production by over 50%. My estimates, based on 8% recovery (IIRC this was their revised recovery target) is they require 250kt of KTMS salts per qtr. "

Some of those figures may be out of whack for final production tonnage and KTMS required.
Their figure are 8:1 Na:K for the KTMS. 70-85% recovery. Which is roughly 10% (the Na is in the form of NaCl, halite)
NaCl is 54g/mol while KSO4 is 174g/mol. So that does shift the tonnage of SOP produced substantially when operating to spec.