To take a simplified example, if you have a $20,000 student loan at a 4.29% interest rate, you would have been charged a total of $3,722 in interest during your four years in college. If you make no interest payments until you graduate, at that time your loan principal would be $23,722, which means the monthly payment during your 10-year payback period would rise from $205 to $243, and you would end up paying $1,152 more in total interest payments.

How did she get these values?