nh discbine top cap assembly

To any owners of nh discbines, discbine dr, and any others I pose the question why are topcaps non servicable? Nh doesn't sell bearings or the shim between them. I have a stack of these that I have replaced with new when they get a lot of play. $250 or so apiece. That's fine for the seller but it seems like a waste when the expensive parts the housing and splined shaft and gear are fine. On the new Idea cutterbar you remove or added shims as necessary to keep within tolerance. No numbers on bearing and the shim ring is a peculiar little cuss. I swear if I could mill a few thousands off it she would be like new.