How do I accurately calibrate an external on-camera LCD monitor?
It is because you are calibrating the monitor correctly however the other two, The Sony LCD and the Computer are probably not correctly color calibrated in the same way, I know that my laptop seems to desaturate colors around the 30% mark and when compared to a calibrated monitor it looks quite a bit different...I would assume this would account for why they are different, if you want it to look like it does on the laptop or Sony Camera then you will need to do just as you have, then eyeball it to bring the saturation back down.