How far off would the tax liability estimate on a filing extension have to be for the IRS to void the extension? For example, what if the estimated liability was for 60% of what the total amount per the actual filing ended up being and the 60% was paid at the time of the extension. Would the IRS void the extension and charge a filing penalty on top of the payment penalties and interest on the 40%? To be specific, I know there will be payment penalties and interest on the 40%, just curious if there would be other repercussions after the actual filing was made in October and the additional 40% plus estimated penalties and interest were paid in full at that time as well.
Thank you.
