This is a fusty old standard, going back to the 60’s. I don’t know from where it originated (probably one of the DX Clubs, and maybe only among orthodox hobbyists).
Only AM stations heard within ten miles of your original den and original totals list ‘count’.
10 1/2 miles — nope.
Our group of four DXers near JFK Airport adhered to that 11th Commandment. So did another group of DXers in north Queens, near Bayside/Throgs Neck Bridge.
Short Wave was another matter. Our coterie figured that if a station from around the world came in around the world, then the restraints got loosened.
25 miles or less from the main den for short wave.
There were some DXers that would not officially count a station until a QSL was received.
Others would be content if the station were taped.
Hobbyists have their idiosyncrasies while they collect their pursuits, whatever they consider genuine.
Anyone else here have a standard or two as a guide?