Late coming quota and deduction from payroll

Hi,

Please give me some idea to solve the below scenario for positive time management:

1)Generate quota of 17 hours for a year as employee can come late upto 17 hours in a year.
2)Employee can be late upto 17 hours during one complete year. No deduction will be made.Quota of 17 hours will be reduced with each late coming entry.
3)If employee is late more than 17 hours salary deduction will be made as per late duration. 
for example if emplyoees regular workschedule is from 8-5 and he came at 815 in the morning then these late 15 mins will be deducted from 17 hrs quota and this quota will be updated to 16.45 mins. when 17 hrs completely used then decution of salary will be made.

its urgent. Pls reply ASAP
Thanks