Was the amount of withholding tax different from 2018 to 2019?

The new law states isf your claiming ACTCThis year you have to file a 1040xor a 8812form wich turbo tax did for mw this years i belive this is what the hold up is for many people . And the IRS is double checking the verification of people . 

The amount of Federal withholding is based on your filing status, how often you get paid during the year, if you claimed any allowances on your W-4 form.

For 2018 the Federal withholding amounts were lowered due to the changes in the tax laws. The Standard Deduction increased  and the Federal Tax rates decreased.

For 2019 the rates did change by a small amount due to the increase in the Federal Standard Deduction.

If you are concerned about the amount being withheld from your paycheck you can increase or decrease the amount with you payroll department by filing a new W-4 form.

Link to Why Is My Check So Small After Taxes?

What is ACTC?

ACTC is the "additional child tax credit." If you can't use all of your child tax credit because it is more than your income tax, then you can sometimes qualify for the ACTC, which is simply more child tax credit money that is added to your refund.