Why is actual tax deduction rate on mortgage interest much lower than pre 2018 tax reform?

I've always filed married jointly and my household income is in 33% income tax bracket. I have a $450,000 mortgage refinanced on Sep 2017 on my main home(I only have one home) .

 

I noticed that before 2018, if I enter $10,000 mortgage interest in TurboTax, the Fed tax due reduces by about $3,300.  The actual tax deduction rate on the mortgage interest($10,000) matches my 33% tax bracket. This is true for tax year 2017,2016,2015 ... all the way back.

 

But in 2018 and 2019 tax return(after tax reform), my household income remains pretty much the same that leaves me in 32 % tax bracket.  If I enter $10,000 mortgage interest in TurboTax, the Fed tax due only reduces by about $1,200. The actual tax deduction rate on the mortgage interest($10,000) is about 12%. This is much lower than my income tax bracket 32%.

 

I can't find any information on why it is like this. My mortgage situation seems to be eligible for fully deductible interest. Did I do something wrong or not aware of some of the new tax rules? My state is CA if that helps.

 

Thank you for any help you can provide!