Green Sheet averages, since their introduction have always been exclusively league meetings, however many books and magazines carry averages calculated from all official meetings, which naturally include KO Cup matches, and in seasons such as 1987 for example, teams raced once in the league and once in the League Cup so all meetings are usually included.
I believe the late Bryan Seery was the first statistician to calculate averages and always included bonus points .......it's only in the last year or two that bp's have been excluded from team building averages, but even now they are included in official averages.