Retirement tax questions

Thank you.  Do you know how the repayment calculation works?

 

If you take out 50K pay 5K in taxes and you repay 21K -  

is the math:   50K - 21K = 29K and that is spread over three years  minus the 21K (repay)

Turbo tax is taking the 50K dividing it by 3  or 16,667 and then subtracting 21,000 (repayments)


If they apply all the repayments this year -  what about 2021 and 2022?  I'd owe 16.7 every year if I don't prepay in 2021?    

 

can someone explain the repayment calculation?

 

thank you