TSP Center

Whenever I start monthly TSP withdrawals and request extra federal withholding from the payments, do I need to file an IRS Form W-4P, or will TSP automatically take care of that? TIA

I just got off phone with TSP, representative was able to update my withholding for me in the system (hopefully). I didn't change anything from when I started LE payments but they dropped my additional withholdings and are blaming it on the IRS change