The Trump administration is pushing businesses to withhold less in taxes by February. Democrats want to make sure that 2018 tax tables for the new law are accurate and don’t show artificially low rates. That would cause people to think they got a bigger tax cut than they did and they won’t know the truth until 2019 when they file their 2018 returns. I wouldn’t put it past the Trump administration to do this.
This article has a table with estimated tax deduction changes.
Sad!