In article ,
says...

Bottom line, was the installer incompotent and this was doable, and if
so, how is it done. If it is NOT possible to miter/cope those joints,
is the decorative blocks the ONLY solution or are there other options.

Frankly, I think the decorative blocks look like ****

he's correct. the "projection" (relative height) of the inclined piece
increases. someone asked me aout this a few of years ago....never had time to
work it out in detail:
http://users.adelphia.net/~kimnach/w...poundangle.htm.