I may have damaged my 1.4x TC somehow. I have never dropped it nor even bumped it hard on or off camera. It may have just been a bad copy from the getgo.
I don't know anyone near me who has a 1.4x that I could try on my 200-400mm, but I do know a guy who has a 1.7x. Maybe I will borrow his and try it.
FoCal does open your eyes to things you never really considered before...good and bad.
All of you guys seem to get higher QoF than I get regardless of body/lens. Maybe I need to try printing my target again. It could be the target and not the camera bodies. However, I don't think the quality of the target results in QoF reduction when I put the TC on...but I have been surprised by other findings.
Regarding the amount of work to calibrate lens and TC combos, I was not paying attention to the number of clicks FoCal was making when I first started. If you do a full set of calibration/tests for every lens, you can end up with a pretty high number of clicks just in the calibration and testing. I was averaging well over 1,000 per body...partly because of the FoCal failures while calibrating...resulting in restarts.