The Ten eats a lot of chains. I think it is the bad transmission damper which causes the sprocket to move side to side wearing the chain's O-rings and finally losing its lubrication from inside. I have never lengthened a chain on my Ten (in 90.000+km) to its limits, there are tight spots in it before it stretches too much.

In Holland a guy made room for a second bearing in the sprocket carrier which can be a good solution.

BTW, I always buy my chains (VX) sprockets combo's on ebay for less then 100 euro's