Yes, the income that could have eventually been reported to you on Form 1099-MISC can stay on Form 1099-K for tax reporting purposes. It is a best practice to keep good records to trace all the income sources to prove what is being reported.
In the event of a partial reporting on the forms, which potentially exists with Form 1099-MISC, Form 1099-K, etc., the best practice is to always report it on the tax return exactly as it was received initially.
Then, make the adjustments as necessary to get to the accurate total.
For example, if a business made $10,000 total, receiving Form 1099-K from PayPal for $7,500 which included $7,100 from one main source and $400 from someone else also on PayPal, but still business related, then in TurboTax, report $10,000 by entering Form 1099-K for $7,500, and add a line for Other business income of $2,500. Keep business notes which would track all the sources of income including each of these components.
I'm glad this is helpful!
@drnag
