Any active users of tca_correct? Optimization issues.

Is there anyone actively using tca_correct?
I am using it to correct lateral chromatic aberrations of microscope photos, but I am only getting good results when optimizing for C,V.

If I add B, or AB to optimization variables - results are completely wrong, image becomes much worse than before tca_correct.
It looks like Hugin it too rough when optimizing A and B which are very sensitive. Any suggestions how to overcome this?

CV-only correct 80% of CA, and I can see there is some room for improvement.