Hi,
This site also maybe helpful to you. It’s a UK site so they call crown molding (cornice) and spell molding with the letter U in it (moulding)same as we do here downunder. But to tell you the truth the way you guys spell it makes more sence.
When you take a look you will notice with the first piece of interal crown molding gets cut straight then the molding that joins it is cut at 45 degree’s.
It is so much easier to do it this way for internal joins than cut the two pieces at 45 angle.
http://www.diydata.com/decorating/coving/cutting_cornice/cutting_coving.htm
regards from Noelene