Hi, Karl. Yes, this tax collecting is confusing! Airbnb should be collecting 7.5 % on your behalf because Osceola County adds a 1.5% Discretionary Sales Surtax to the Florida Sales tax.
Since Osceola's Tourist Development Tax (TDT) is 6% and Airbnb does not collect it, it is your responsibility to collect and submit it. Calculate the tax on the total accommodation charge plus cleaning fees and any extra person fees. TDT = (Total Room Charge + Cleaning + Extra Fees) x .06. Also mention in your listing that you will be collecting 6% Osceola county tax upon the guest's arrival, if you choose to collect this tax.
The other option is to absorb the tax in your nightly rate and pay the tax from your gross earnings. Here is where I may lose you...
I absorb the tax in my earnings, but I do not like to pay tax on tax paid (double taxation). I say Airbnb’s Gross Earnings (GE) INCLUDES the county's tax, so I reduce this amount by the county's TDT percentage (in your case it's 6%). This gives me the county's Gross Rental Receipts (GRR). My formula goes like this: GE = 106/100 GRR. Solve for GRR by multiplying each side by 100/106, which is 100/106GE = GRR. Then, find the county's tax by multiplying GRR by 6%.
For example, say Gross Earnings in February was $930 (including the cleaning fee). The formula is 930 = 106/100 GRR. GRR = (100 x 930) / 106, which equals 877.36. (This is the Gross Rental Receipts to report to the county.) Then, multiply 877.36 by .06, which equals 52.64 (the Tourist Dev Tax to submit to the county). To verify this is correct, add 877.36 to 52.64 and you get $930 (Airbnb's Gross Earnings).
Hope this is clear and makes sense to you. Good luck.