We tried testing the primary and overtime feature for billing. We selected
both options and put in the rates corresponding to the charges we want. This
account does not have a monthly charge. The test account is billed only for
the time it uses. 
in our example:
Name:Promo
standard time :0                 over interval 3600
standard interval:3600           over charge     40
standard charge: 40
Primary
start 8:00                        regular charge 80
stop  16:00                       over charge    80
The problem here is that on the next billing statement, the account is
charged 0.00!
the account is on a balance forward , monthly billing method.
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