My understanding has always been what yours is 4 trails, and what you were told; ie a cat 2 appr has cat 1 reversion when the rvrs are equal or greater than the cat1 minimum rvr, and if rvr is less than this it's a "cat 2, no reversion", (ie dont revert to cat1 minimums if eg you get YD failure, one side nav fail, persistent gs/loc dev). I dont see the relevance of the other stuff except that the beacon/1000' is the point before which you must receive the deciding rvr.