I bought two of these Aaen pipes and both had fitment issues, amazingly enough they both had different fitment issues. We had to do some tweaking for them to fit.

Something that is built in a jig should all have the same fit.  It sounds like it may not be a jig problem.  It sounds more like a craftsmanship issue with consistency from one pipe to the next.   All pipes should fit or all pipes should not fit if they were all  made in the same jig.  With the low production numbers of these pipes there is no reason for having more than one jig for the Lt 500.