IRS Notification of error related to Refundable Child Tax Credit, it's about SCHEDULE 8812 sheet 5

I received a notification from IRS today, to say I owe $1,000 which is due to an error in my Form 1040 about Refundable child tax credit.

 

1040_8812_child_credit_section.png

 

look like IRS is expecting the highlighted cell to be $1,000, but I'm not sure why, 

 

My total income is between $150,000 and $400,000, I think it would be apply to this:

 

First phaseout: Income exceeds the above thresholds but is below $400,000 (married filing jointly) or $200,000 (all other filing statuses). Your total credit per child can be reduced by $50 for each $1,000 (or a fraction thereof). This phaseout will not reduce your credit below $2,000 per child.

 

In this case,  each child's credit would be still $2,000, is my understand correct?