Reduce MAGI for Health insurance subsidies

[Farha15p]

Hello everyone one, 

I have a quick question about the MAGI 

We are a family of 3, myself, my wife and my baby boy, and we live in Florida. 
In order to get the health insurance subsidies I must keep my AGI under 85K. Sometime my job ask me to work overtime and I am worried that I might go over $85K and end up paying the subsidies back when I file for 2020. 

My wife gave birth this year so I had to do a low deductible plan with high premium. The health insurance agent told me that if make more than $85K I will have to pay back $12k in subsides. He told me to try to keep my AGI under $85K my sending money to my retirement account.

My company set us up with Simple IRA account and at the end of every year I get Form 5498, Please see attached what I got last year. 

My question if I feel I am getting close to the $85k limit and I ask my boss to send my paycheck to the simple IRA account to keep me under $85K would that lower my MAGI so I dont pay the $12K back? 

I am asking because when I filed my 2019 taxes my MAGI did not lower by the amount I contributed to my simple IRA account in 2019. it actually stayed the same. What I missing here? 

[MinhT1]

The amount you contribute to your Simple IRA are in fact deducted from your MAGI. However, you do not see the amount deducted on your form 1040, because your contributions are already deducted from your gross wages and the amount net of deductions is reported in box 1 of your form W-2. Please check your form W-2. Box 1 should be smaller than box 5 by the amount you contributed to your Simple IRA.

[AmeliesUncle]

As was mentioned, retirement contributions through your employer are already factored in to your W-2.

If your income is getting too high, contributing to a Traditional IRA may be easier than adjusting your employer retirement.  You can contribute to a Traditional IRA as late as the regular due date of your tax return (usually April 15th, but this year it is July 15th).  That way, you can contribute the exact amount that you need to qualify for the Premium Tax Credit.