Problem with Iteration on Service Charge

Question

Have a problem with a question with Service Charge for Charging a customer for house cleaning (for instance). If the charge is $80 for the first 5 hours, and $5 for every other hour. 

 

While I know how to make the first charge, what is the syntax for getting additional hours. 

 

I will also need to add tax to the total charge.

 

Thanks