Well the kite is not folding in half is it? So it appears fixed in that regard. There appears a tip issue with associated bridle issue there. I think he hasn't lengthen Z to have the same effect as he had in the picture, where B appears 1.5cm shorter. Lengthening Z more may improve the tip but it is better to fix the tip bridle if it has LCLs so it can be done easy. He could stretch the bridle there at the LE, but it is hard to tell with out a line plan exactly what needs doing. Looking at the second video again though it is definitely a B bridle as it reacts to bar movement. Makes sense as this is what kite designers tend to do, move B and C forward on the cord towards the tip. In which case shortening B is not a good solution, shorten C would help but it will just throw the rest of the bridle out. The tip bridles need to be fixed.
As to regards to B, this will need to be lengthened more with C and Z in ratio to restore full depower. You need will need a line plan to calculate the amount or generally it is till B goes slightly slack (bowed) when bar lines are at max depower (rear lines well bowed).
As to kitexpert, he is a bit of a strange one. All evidence points to him being a Tube kite designer, you just need to talk to some, read their posts or see that new BS article. He doesn't seem to actually use foil kites much. Which is more strange because he gives lots of advice on them, and incorrect like above. Adjusting Z has the biggest effect on foil kites than any other bridle. It is commonly known and understood. Flysurfer has perhaps muddied the water by going about it in a strange way of adjusting both BandC to get much the same effect.