求助达人们关于付款方式

一票出口印度的货，我方发邮件给客户表明不接受dp，后来客人回复如下： since we are in initial stage of starting business together, i think we should not talk much more regarding the payment terms issue. ok, you send the original bl scan copy, invoice scan copy & packing list scan copy to us. also, immediately send the original copy to our bank also and give us the dhl number. after getting the scan copy, my boss will try to pay you the 70% payment separately & when bank will receive the papers, my boss will take the money from icici bank by showing our payment copy. then we can get this 70% payment from bank immediately. i think, now you are quite comfortable to deal the same. also, give us the pi for next 4 shipment separately, so that before finishing of chinese new year, we can open 1-2 lc for next consignment. wishing a good business relationship ahead. 请问以上貌似和dp没什么区别，为什么客户要求把原件的复印件寄给对方的银行？这和印度的银行付款方式有什么？ 请教群里的达人们。。。