A. Time Based - Default set-up. deduction is start date and end.

B. Amount Based - This is for loan. start date and loan amount. Will end automatically once zero balance.

C. Count Based - This is for allowance. based on the counts and amount of deduction/income. 

Sample:
Meal AllowanceAmount: 400Monthly amortization: 200Credit Method: Count BasedCount: 3
June 15 - 100June 30 - 100July 15  - 200