I'm not following you. Do you have an example?
Let's say you and I make the same amount of money, and the IRS estimates that at our level of income we will see a $1,200 tax cut this year. They will, in theory, adjust our withholding down by $100/month.
You normally take the standard deduction, which is greatly increased. Sweet.
I have a home equity loan and several adult children (huh?) living with me, making me one of the probably few people who are going to end up paying more under the new laws.
If we look only at our paychecks this month, we're both going to feel like we got a nice tax cut. Come next spring when we look at our actual tax burdens, I might not be so happy after all.
While I think that overall most people will see both a reduction in withholding and a reduction in total tax burden, my original point was simply that one does not necessarily imply the other.