Thank you for the valuable information. I am seeing exactly what I suspected: That ANSI or any other standards organization does not publish a specification. I am attempting to do tolerance stack-up and optimization on wooden furniture assemblies, and need to know exact limits on the shoulder size of the screws we use. Looks like this information will prove difficult to get.
Be blessed in Jesus Christ our Lord, confessing Him before all men, proclaiming His wonderful goodness!