The one you posted appears to be for determining the taxable amount of your traditional IRA distribution on the Traditional IRA Distribution Worksheet and should be recorded on TurboTax's IRA Information Worksheet. (It appears that TurboTax detects the missing value on the Traditional IRA Distribution Worksheet but does not detect the missing value that would need to be on Form 8606 line 6 if the Traditional IRA Distribution Worksheet is not being used.) The other is for determining a penalty on an excess traditional IRA contribution and is recorded on TurboTax's 5329 form. It's possible to have both situations on a tax return.
