LCL
You have to remember though that TCX constantly rotate the 757s throughout the whole country so while certain reg's have maybe gone tech "once" in NCL, that doesn't mean they haven't gone tech somewhere else in the meantime.
YL-LCL on the other hand is based only at NCL so it may seem that it is tech more than any other aircraft in the TCX fleet as you are monitoring NCLs departures.
Plus the reason that the 757 is stepping in to do flights when it is tech is because TCX have a 757 with a very limited flying programme which is there to pick up the programme throughout the country when things go wrong.