I do not use ATX but it seems to me there must be something on the estimated tax screen that is not factoring in what was withheld in the current year. Sorry can't be more help.
I was talking about XYZ doing the closing of the books or proration based on days of ownership not ABC. ABC Inc and ABC LLC will get their own K-1 with their share of profit and loss. Who of the three entities do you prepare taxes?