Be aware that regulations section 1.469-9(g)(3) requires the taxpayer to file the aggregation election with his or her original income tax return for the year the election is made. The regulation states that once the taxpayer makes such an election, it applies for that year and for all future years during which he or she qualifies as a real estate professional.
Now as far as I know, the TurboTax program does not generate any such statement, and such statement can not be e-filed with an e-filed return. So if you did not write up such a statement and include it with your mailed return (not e-filed) then the IRS would not consider your rental properties to be aggregated into a single activity.
https://www.irs.gov/pub/irs-drop/rp-11-34.pdf
