He "misspoke"

In a Friday interview with the New York Times, McConnell acknowledged that some working families would end up paying higher taxes if their bill passed, contradicting his comments from earlier this week.

“I misspoke on that,” McConnell told the newspaper. “You can’t guarantee that absolutely no one sees a tax increase, but what we are doing is targeting levels of income and looking at the average in those levels and the average will be tax relief for the average taxpayer in each of those segments.”

  TPM

What's an average taxpayer? What are the levels?  We know how averages work.  Ten people with 1$ gives an average of $1, and they're all getting the average.  Nine people with $1 and one person with $1000 gives an average of $100.90.  How many of those ten people have anything near the average?

The average is meaningless if the "levels of income" are wide.

And I beg to differ on another point: you can indeed guarantee that absolutely no one sees a tax increase.  Not that that would be the best solution, but it can certainly be done.

A Times analysis found that millions of middle-class families will see higher taxes under the bill, which disproportionately benefits corporations and the country’s wealthiest households.

"Some" working families.

...but hey, do what you want...you will anyway.