I think something wrong with global/job configuration inheritance. I always expect to have default values in global configuration and ability to change any setting in job configuration. AFAIK usually it: new job uses global configuration as it default values, all values then saved to job configuration and global configuration doesn't override them. In this case if you want do mass changes from global configuration you should use groovy script that will do mass changes using jenkins api (i.e. scriptler plugin) or other ways.