After you file

Thanks for the quick response.   Let me ask my question with a little more detail. 

 

When I entered my numbers, I put in the expected gross amount for the year, the amount of federal taxes already withheld each month and accumulative for the year after two payments this year.  And the system came back with a number around $5k that I would owe if I didn't adjust my withholdings.  When I had the system fill in the information on the W4p form, it calculated the additional amount needed to be withheld in addition to the standard deduction, which was $115.  And put it in the 4c box. 

 

Can I assume this amount is correct and I won't owe any additional taxes for the balance of the year if I have an additional $115 withdrawn each month?  Or do I need to calculate the additional amount based on the $5k / 10 months of payments for the remainder of the year which would work out to $500 additional withheld per month?  Or is it some other number?