Unused was implied.

I'm saying (as the union is) that picking up 5 short calls that remain unused will pay 76, and if you picked up all 5, then the company can assign you 5 more, and even if they remain unused, you will not get paid for any of them. Remember, separate calculations.

Say a total of 8 unused short calls:

5 picked up, 3 assigned (in that order): pays 76
4 picked up, 4 assigned: pays 76
3 picked up, 5 assigned: pays 76
2 picked up, 6 assigned: pays 77
1 picked up, 7 assigned: pays 78

Paragraphs a and b are separate calculations. You need to be assigned more than 5 and have them remain unused to get paid above 76.