Yours is the best answer, but of course, not so good I think I can't add more. ;0-)
The meter offers, say, one hour for 25cents, not one hour per 25cents. If it says one hour, you only get one hour and can't pay for more.
In the 50's and 60's, the cop would make chalk marks on tires, and when he came back again in say, 70 minutes, people with chalk marks could get tickets. Not sure if there were meters in this case, or if the cop even looked at the meters. And I think t his was before there were meter maids. Er, meter people. This was downtwn Indianapolis, near the big department stores.
Great movie: Revenge of the Meter People.