Rerating Multiple Events

Hi,

Can anyone confirm what is the expected result after rerating multiple events.

Base Price 1Rs/ Min

1. Rated a CDR for 10 Mins -> Amount charged 10 Rs

2. Changed price to 2Rs/Min and started rerating pipeline

3. Amount rerated is  10 Rs + ( Existing bal ), so Total 20 Rs

4. Changed price to 3Rs / Min

5. Now again i am extracting the events using pin_event_extract

6. Restarted rerating pipeline

Now what is the final amount that should impact to customer balance ? whether it is 30 Rs or 40 Rs ?

Thanks in Advance !!