Help with a sentence

Hello all, I'm writing an article in English on the long duration of episodes in television series in Turkey, which is the world's second biggest TV series exporter after the United States.

I would like to write an explanatory sentence for the information below:

"A 13-episode project is eligible for exports since it is sufficient to cover a season in overseas countries, it is equivalent to 26-episode when broadcasted abroad."

Basically they are trying to say that it's related to export concerns because when they shoot 13 episodes it covers the whole season since the country which buys the series will divide the series and use them to cover the whole season.

It's less costly for the production company.

I would like to start my sentence like:

"The main incentive behind the longer duration of the episodes is...."

Or something like that.

Hope it is clear.

Thanks in advance!