@Jim *******
you are talking about two different things and trying to make them sound the same when they aren't.
The "days" you're talking about are the exact same regardless of if the tourist visa is single or multiple entry. You get 60 days when you enter Thailand. Those days don't start until you actually enter Thailand. On a single entry they start when you enter Thailand. On a multiple entry they start when you enter Thailand.
The visa validity is active from the day the visa is issued for every visa. These two things are not the same. Visa validity and permission to stay in Thailand are different things completely.