Credit Checking Calculation by allowance

I am trying to understand how the system calculates the credit limit when using allowable %.

For example, I have the following set up:

Limit Type: %

Code Type: O

Age From:   3

Allowable %: 1.0000

Looking my Credit Check screen (P42050), I see the following:

Future: $0

Current: $0

31-60: $71,122.00

61-90: $50,580.00 (I am assuming this is my period 3 or bucket 3)

Amount Due: 121,702.00

Credit Limit is 1,000,000.00

What is the customer credit limit in this case? How the system calculates?

Thank you in advance.