CP2000 for 2019 indicates I owe $6539 to IRS, but Turbo Tax says I owe $5877 when I add the missed income. Why are they different? I have to amend State

According to the CP2000 instructions, I don't need to amend my federal return, but since I have to amend my state return I entered the additional income in TT and the amount owed shows this difference...how do I know that my state amended amount owed is accurate?