Greg, BPs do double clutch.
Sebrina, this means that you can put BOTH males to your girl alternately and maybe will luck out with both males fertilizing some eggs and you get a two-fer at one time without additional stress on the female.
But as to breeders breeding year round, that isn't be cause they do what you purposed, but they manipulate the snakes environment and stagger the girls for breeding meaning some are cooled later (environment manipulation) and/or also BPs don't all grow their follicles at the same rate. So some may lay their eggs later in the season. It simply means they breed the girls when they know it's time (follicles) instead of waiting for a particular time of the year.
(hope this makes sense).