taxnovice15,
First of all, I sincerely congratulate you for researching this on your own and landing on IRS Publication 1212!
On page 6 of that publication (https://www.irs.gov/pub/irs-pdf/p1212.pdf) there is a recipe for how to lump everything into OID:
"Choice to report all interest as OID. Generally, you can choose to treat all interest on a debt instrument acquired after April 3, 1994, as OID and include it in gross income by using the constant yield method. See Constant yield method under Debt Instruments Issued After 1984, later, for more information.
For this choice, interest includes stated interest, acquisition discount, OID, de minimis OID, market discount, de minimis market discount, and unstated interest, as adjusted by any amortizable bond premium or acquisition premium. For more information, see Regulations section 1.1272-3. (https://www.law.cornell.edu/cfr/text/26/1.1272-3)"
This does require you to calculate what the "constant yield method" entails which is detailed on pages 9-10. And, yes, I've done that calculation for every Treasury security, TIPS or not, that I've ever bought. I chose to use an accrual period of 1 day, but any length no longer than 1 year can be used.
Hope this is not too arcane and has been of some help.
