I am PS Pro:  I cannot open article.  But on closer study it is based on 80% of current tax, not 80% of 2017 tax.  

Great to see you in the community. When I first looked at your post, I thought it was for Lacerte, I see that it is ProSeries Professional. Please see this post from the IRS:

IRS expands penalty waiver for those whose tax withholding and estimated tax payments fell short in 2018; key threshold lowered to 80 percent

https://www.irs.gov/newsroom/irs-expands-penalty-waiver-for-those-whose-tax-withholding-and-estimate...

Thanks for the confirmation.

Helga

Thanks