Is the Additional Medicare Tax form being calculated correctly? When married and filed jointly it appears to be calculating based on $200k instead of the $250K (per IRS).

The IRS website (https://www.irs.gov/instructions/i8959) says the threshold for additional Medicare tax kicks in at $250,000 for those married and filing jointly. My W2 medicare wages are $230,331.50 (and my wife doesn't work outside the home) and my company withheld $29,825.63. TurboTax federal withholdings says $30,099. So in my case, there should be no additional medicare tax withheld but when I work it out, the extra withholdings TurboTax is claiming is showing they are using the $200,000 figure instead of $250,000. I can verify this by taking the income over $200,000 which is $30,331.50 times 0.9% (0.009) medicare tax rate which is $272.98. Add this number to my federal withholdings results in the total seen in TurboTax: $272.98 + $29,825.63 = $30,098.61 (or $30,099 rounded). Why is TurboTax using the $200k threshold when it should be using the $250k threshold since I'm married filing jointly.