Process Effectiveness - Payment On Time Index

Using ponderation as 75% for payment on time and late posting as 25%, the Aug 2019:

Payment on Time (Volume) - 89%

Late Posting - 4.5%

We can see that 89% Payment on Time will fall under the score of 2 and 4.5% late posting will have score of 3. With that, the result will be (2 x 75%) + (3 x 25%) = 1.5 + 0.75 = 2.25