If you have:
There a subtle difference when the actual ticket inventory is created.
Tickets are created at the same time as the performance is created. One ticket is created for each seat in the theatre so that tickets always exist for every seat. This ensures that there can never be a double seating issue!
Tickets are created at time of sale and a ticket can represent an admission of a number of people (e.g. admit 10). If a ticket always represents one admission, the number of tickets created will be similar to reserved seating.