You are correct that the TurboTax program allows only one "special" adjustment for each separate 1099-INT entry, on Form 1040 Schedule B.
The solution to your issue, then, is to simply take your single 1099-INT amount and "break" it up (or out) into multiple entries. As long as the total amount of interest (matching the 1099-INT figure) is correct, it doesn't matter how many additional smaller entries you make on Schedule B, because the IRS won't care. All that concerns the IRS, really, are your ending totals, as that is what your income taxes are based upon.
An illustration with numerical examples will help demonstrate this method; and then you should be able to adapt the principles to your own individual circumstances.
In this hypothetical example, I own a bond that paid me $1,000 in interest for the tax year. Furthermore, I have both an Accrued Interest Adjustment and a Bond Premium Amortization Adjustment to make (both items on the same bond issue). What I do then, in TurboTax, is to take my $1,000 of bond interest (from my hypothetical Form 1099-INT), and split it up into two different amounts of $500 each.
Then, when I go through the TurboTax program, and enter my data, I can make an Accrued Interest Adjustment to one $500 amount, and then a separate Bond Premium Amortization Adjustment to the other $500 amount. In my example, the total of these two adjustment items is $125 ($75 for one, and $50 for the other, respectfully).
A series of screen-capture images, taken directly from the TurboTax program, further explain what this looks like in visual format (simply click the images to open).
With this method I can satisfy both the IRS, and the rules of the TurboTax software. My total interest is now reported correctly on Schedule B, and shows what I want it to (in my hypothetical example). Following those principles, you should be able to do the same thing with your own 1099-INT.
However, if you have further questions, encounter any difficulties, or just want to speak with a live tax expert who can walk you through your TurboTax entries (including the ability to screen-share with your computer), please feel free to contact us. We would be happy to help you (and as a paying customer, the call is free to you). Here is a link where you can create a support ticket and reach us:
https://ttlc.intuit.com/replies/3300041
Thank you for asking this question.
