Amended 1099-R Distribution

I filed my taxes and then got later a 1099-R on a small distribution I received during the year.

 

The distribution was for $5770

Federal tax: $1154 was withheld.

 

So, they withheld 20% which is correct and because I'm under 59 1/2 I know there is a 10% charge on top, which would be another $570 (roughly).

 

In Turbo tax, it says I now owe $688 to Federal after I inputted everything.  Any insight on this? I've tried getting an "Expert" several times and the "helpful" help on the side won't connect me.