IRS increased underpayment penalty 153%

[Mytwocents]

I just received a letter from the IRS stating they increased last year's underpayment penalty by 153%.  I'm retired and most of my income is from investments.  I choose to skip the estimated tax payments because in general I make more money from my investments than the cost of underpayment penalty.  I've used Turbotax for decades with hard copies mailed in.  Yet here in November, they send me a letter demanding 153% more money in 3 weeks claiming they "found an error".  Doesn't Turbotax guarantee that all calculations are correct?  Shouldn't Turbotax pay the extra because of the "error"?  How do I get through to Turbotax because so far I can't find a way to contact them.  Thanks.

[DoninGA]

Interest and penalties are paid by TurboTax for a calculation error in the software but not any additional taxes owed.

See this TurboTax support FAQ for the calculation guarantee - https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/turbotax-100-accurate...

Contact TurboTax Audit Support Center for assistance with the IRS letter you received - https://support.turbotax.intuit.com/irs-notice/audit-support/

[Mytwocents]

Thanks for the links.  I should have been a little more clear in that the 153% increase is on the underpayment penalty only, not the taxes.

[Critter-3]

OK ... the program only calculates an ESTIMATED underpayment penalty based on the info you provide of when you made the payments up to the filing deadline of 4/15.  The IRS reserves the right to calculate any more  underpayment penalties + interest based on the info they have of when and how they actually received the payments and balance due on the return.