I called HR and figured it out. I did not get a complete answer from HR, but it was satisfactory. My paycheck changed because my status as an employee was re-classified in December 2019, based on Colorado PERA, which is the retirement organization for state workers in the state of Colorado. I teach community college.
Upon hire in July 2019, I was considered an "old" employee because I previously had a Colorado PERA account in 2006 to 2011. In December 2019 central payroll learned that I cashed out my PERA accounts in 2011, which disqualifies me as an old employee.
Starting Jan 2020, I am now considered a new employee, which is actually better for me. As a "new" employee, I get a employer contribution toward my 403b of $548/month. As an "old" employee, I was getting an employer contribution of $362/month. This is an increase of $186/month.
Interestingly, the percentage contribution of the plan did not change. However, the "Applicable Gross" did change. My current monthly salary is $4016. As an old employee, the "Applicable Gross" is $3,488, so my employer contributes 10.4% of $3,488, which is $362.
However, as a new employee, my "Applicable Gross" is $5,269 and I get 10.4% of $5,269, which is $548. I get $1,253 of contributions towards my health insurance. PERA now considers that to be part of my total compensation and contributes 10.4% of my total compensation.
Lastly, when I asked HR, how do they calculate "Applicable Gross" to be $3,488/month for "old employees" when my base salary is $4,016,/month, they said they didn't know. They just said it is a complicated formula created by Colorado PERA.
It kind of sucks for "old" employees that their "Applicable Gross" is lower than their actual salary. Isn't a 403B contribution supposed to be based off of your based salary, not a number less than that?