coverage service contracts

I have two questions:

1. How coverage service contracts control the limit when coverage amount is finished ?

2. Is that possible to have coverage for material on units?   

Question 1

If You have coverage amount and service request charges If a coverage value and the service request is made there is no control charges against discounting the same value of coverage. For example there is a coverage of $ 10,000 and a service request charges are $ 8,000 for the first time, the value is charged to the patient free of charge and the second request are charged again for $ 7,000 and redisplays that is covered by $ 10,000 being the 2,000 that you were right the first service request. For which controls I already use the coverage and