Social security taxable income mistake

I think Turbo make a significant mistake on calculating taxable SS income for 2024. My combined SS income was $67,968. Based on my entire income (well above $44,000), 85% of that should have been considered taxable income. But Turbo inexplicably said only 65%, or $44,460, was taxable. The IRS of course pushed it up to 85% in a letter to me that increased my tax liability. 65% isn't even a threshold under the IRS, far as I know! I wonder how many other people had this happen to them? And by the way, trying to get Turbo reps to respond is more painful than root canal surgery. I'm still awaiting an answer. What about that 100% guaranteed accuracy!