Thank you for your input Active 1.

Does anyone else agree/disagree.

I was under the impression that if I have an actual sevice load investigated that that takes precedent over calculated load. Therefore :
60amp exsisting plus 50amp max on new for a total of
110amps on the 150 amp service. 80% being 120amps.
If this is acceptable it would save the customer the
installation of a new panel and a 200amp upgrade which the
exsisting service lateral and meter could handle according
to the Utility Company.