Refinancing a first and HELOC after new tax law - granfathering rules?

[psumnicht]

I have a first mortgage of $800,000 and a HELOC of $100,000

All proceeds from the loans were for the acquisition and improvement of the home and were taken out before 2017.

If I refinance the full amount of $900,000, am I still grandfathered to be able to take the full interest deduction, or will the refinance trigger the limitation at $750,000 of debt?

[NCperson]

walk yourself through Table 1 on page 11 of the attached

that will provide the answer 

https://www.irs.gov/pub/irs-pdf/p936.pdf