Incorrect calculation of line 4b for IRA conversion

[Jones9101]

I am gradually shifting money from a traditional to a ROTH IRA.  This year 1040 block 4a correctly shows $14,300, but block 4b shows $12,300.  I'm certain 4b should be $14,300 but can't figure out how to change it or why it is different from 4a.  I tried to override the program but was unable to change the number.  Any suggestions.

[AnnetteB6]

A difference in Form 1040 line 4a and 4b indicates that the Form 1099-R may have been entered incorrectly.

Go back through your Form 1099-R screens to be sure that there was not an error entering either box 1 or box 2a.  Additionally, be sure to go through all follow-up questions after the Form 1099-R entry screen to double-check those answers as well.

Use these steps to get back to the Form 1099-R entry screens:

• On the top row of the TurboTax online screen, click on Search (or for CD/downloaded TurboTax locate the search box in the upper right corner) 
• This opens a box where you can type in “1099-R” and click the magnifying glass (or for CD/downloaded TurboTax, click Find)
• The search results will give you an option to “Jump to 1099-R”
• Click on the blue “Jump to 1099-R” link

[SteamTrain]

Well...unless you had some non-deductible contributions to the IRA in prior years...in that case some portion of the total distribution would not be in line 4b....an occasional exception.