It's covered in IRS Pub 936 at https://www.irs.gov/pub/irs-pdf/p936.pdf on page 10. Parts titled "Home Acquistion Debt" and "Refinanced Home Acquisition Debt." Since a refi is not "acquisition" of the property since you already have acquired and own it, I'm not seeing how one can claim 100% of the 2nd refi loan as 100% acquisition debt. Especially since there was a cash out on the 1st refi that did not qualify for home acquisition debt.
