What are the charges for Call Forwarding?

I make 2 trips to the U.S. and get the following in my bills when I get back:
1. In my Aug03 bill I get charged for Call Forward Transfer 32:00 min:sec $6.40
2. In my Jun03 bill I get charged for 2,500 Call Forwarding Minutes $3.00
Could anyone please explain the discrepancy?

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