Totally agree. Scale up of one thing does not mean the same...

Totally agree. Scale up of one thing does not mean the same formula applies, one shoe does not fit all. I was just surprised it was factor in the optimization during testing by SRC but has taken about twelve months to target it as a area that would gain "significant improvements" out in the field.
Of course, I'm speaking as a true part time armchair engineer 5,000 kms from operations.

Interestingly, SRC also did the pilot plant for SO4 (Salt Lake Potash produces premium sulphate of potash product in Lake Way tests (link would be deleted))

"but there should have been enough capability in the plant design and build of changing the variables ."

Looks like it wasn't with the heat exchanger having to be replaced - amongst other things. (K-UTEC)