Where a three day notice is mailed to the tenant, or requires payment to a PO Box, or payment is to be sent out of the county in which the leased premises is located, five additional days must be added to the due date on the 3 day notice. The five additional days for mailing may count weekends and holidays as part of the five days, unless the fifth day falls on a weekend or holiday, in which case the due date shall be the next business day. NGUYEN vs. BROWN, County Court, 3rd Judicial Circuit in and for Columbia County, Civil Division. Case No. 08-442-CC. April 15, 2008. 15 Fla. L. Weekly Supp. 710a.