Vapor barrier between collar beams in insulated roof?

Hello,

our roof is insulated with a vapor barrier. Now I am converting the attic including the collar beam.

Between the attic and the collar beam, between the purlins, I am insulating with 14 cm of rock wool. My question now is: should I also apply a vapor barrier over the rock wool between the attic and the collar beam? So at the green line?

Thanks for your help!

No, you've already got that in the peak - hopefully well executed, as connection errors are often made in the area of the purlins.