Only question I have is the recommended procedure for updates, as version 1.3 naturally doesn't have all PEP levels fleshed out.
Good question George and thank you for the very thorough review!
Version 1.3 has all PEP levels that are currently defined. When additional levels get defined, I add them to the spreadsheet and bump the spreadsheet version when the additions are significant. Minor tweaks or fixes to isolated formulas typically are fixed in the current latest version rather than bumping the version. There isn't a great way to get these changes out to current users as far as I'm aware other than to post some details here about what changes were made so existing users can copy/paste the fixes into their copy of the spreadsheet or copy/paste the data from their spreadsheet into a new copy of the spreadsheet. I hope this helps clarify the current update procedure.
If anyone has ideas how to improve the update procedure, please send me a Purple Moosage.