What is the version of the following sentence with correct punctuation?

One large error in the system was that it was incorrectly calculating a recipients income basing a recipients fortnightly pay on their annual salary rather than taking a cumulative 26week snapshot of what an individual was paid
One large error in the system was that it was incorrectly calculating a recipient's income, basing a recipient's fortnightly pay on their annual salary rather than taking a cumulative 26-week snapshot of what an individual was paid.