Hi Bob:  I appreciate your comments on the start up procedures. In the past few days only happened once and the outside temp was below freezing.  Others have worked like a charm.
 
I have experienced the CTD during a flight however, I can not say it is the FMC. There is a possible scenery conflict that would cause the same thing. It just happened to be when I was making changes to the FMC for arrival into Chicago. Winds changed during flight so the STAR and arrival runway needed to be changed. Just happened to push the LSK and immediate CTD. But like I said I am not convinced the reason is the FMS because it happened twice on the same route in almost the same spot.

 As far as the initial weight goes, you are right there are different versions however, the base operating weight may vary due to different seating and setup, engines etc. I did test my changes an no problems. Takes a bit to climb to cruise as you might imagine. The FMC has recognized the extra and the numbers come out really close to FSBuilds estimate. There is a way to have the weights different with the versions and that requires splitting the initial folder one for RR and PW the other. Haven't tried that yet so we'll see.

Don Brashears