Whether you O/D or transit, that makes no difference regarding CIP buses. But lets compare numbers, I just went into my flightmemory, I have flown in excess of 500 flights with TK in my lifetime ( I am not going to give an exact number for many obvious reasons), over 340 of those flights in the last 8 years or so, since they have gone of their growth spree, and my experience of this airline goes back way over two decades. Even more specifically I have flown over 80 segments since Jan 1 2015, if we want to be very current. Specifically over 93% of all my TK flights have been in premium cabins. Even more specifically I have flown over 80 segments, or 40 RT's with TK since Jan 1, 2015. So that is my data source.
So if you have a better sampling, with better and broader numbers, please feel free to post them. Otherwise here is a little secret for you that I know to be true, TK only has enough CIP buses to hit 80% of all flights max, when you add in those requisitioned for VIP's that lowers the number. Their bus fleet has not kept up with their growth. So if you have had a 95% success rate, that's great, I've had runs where I have had them ten times in a row, and then none the next 8 times. I will say that they are better at providing them to wide body a/c at remote gates than narrow body but then you get the separation issue.Regarding the separation of Biz and Y pax coming off long haul planes, just ask others on FT about their observations of how vigilant the FA's are with this. It's a 50/50 hit or miss at best.