First of all, overtime pay is required for all hours worked over 40 per 7-day workweek. Florida has no law that requires overtime for working more than 12 hours per day.
The way you figure your overtime is to add up all of the pay that you receive and divide by all of the hours that you work, which will give you a "weighted" regular rate. Take that regular rate and divide by 2 to arrive at a half-time rate. Multiply the half-time rates times the number of overtime hours to get the overtime that is due.
Under your example, working 8.5 hours of service work at $13.25/hr plus 5.5 hours of transport work at $10/hr on Monday, plus 8.5 hours of service work at $13.25/hr for Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday, would yield $843.38 for 65 hours of work. The weighted regular rate is $843.38 divided by 65 hrs, which equals $12.98. Since you were already paid $12.98 for each of the 65 hours, you are only owed the 1/2 time premium of $6.49 for the 25 hours of OT, or $162.45. Therefore, you should have received $1,005.63 for working the schedule that you describe.
There is a possible wrench that can be in play which could destroy any entitlement to overtime that you may have. You state that you transport equipment. There is legislation called the Motor Carrier Act which could exclude you from receiving OT. Whether you are excluded from
OT under the MCA is a question that requires much more information. The MCA is very complex. I would be happy to evaluate your situation privately.
If the MCA does not apply to your situation, then I believe you are entitled to OT based on the number of hours you work in a week and NOT because you work more than a certain number of hours per day.