TSP Distirbution - Code 4

You need to double-check the entries you made. There may have been withholding but that doesn't mean that it was sufficient to cover the tax liability. At the same time, that amount of tax due is probably incorrect.

TSP withheld 10% of the distribution amount. My son in law and daughter total taxable income due to the distribution is $402k and taxes due $90k and they have paid a total of almost $47k so I guess they do owe $42k. Does this make sense.