Not parent, but I’d consider 0.001” over 10” to be totally acceptable for home and hobby use and 0.00025” over 20” to be acceptable for general production use (“great” isn’t really meaningful, but “makes parts to spec” is good enough).
That's the specification of a measuring instrument. Commercial VMCs don't hold 0.00025” over 20" even without being loaded. A slight temperature change will throw that off.
