About Delivery Report

Dear All,

I am Amit Khare and working on MMS Client. 

I have to enable delivery reports in our MMS Client.  It will be a SILLY question for you but for me it is necessary for better understanding of DeliveryReports and ReadReports.

Question: 
    (1) Why there is a provision( According to spec 3GPP TS 23.140 ) of MATCHING the delivery reports to the sent MM by means of comaring message identification of the sent MM to the received delivery report ?
    (2) What if some one has deleted the sent MM, How we would be able to perform such Msg ID comparison ?
    (3) In the case (2) above if at all we store the Message ID for the deleted message how long we should retain it and for how many such messages( The messages which require Delivery Reports )?
    (4) is this a better idea to sotre explictly the Message IDs and other information for comparison with delivery report on a mobile phone with limited memory?
    (5) When we have the recipient address available in Delivery Report PDU why do we need to compare this address with the mulitple recipient to whome originally the             message was sent?

Please reply ASAP . I shall be beholden to you all . 

Thanks in advance 

Regards
Amit Khare