求英文高手幫忙中翻英?

The current operating procedure is to receive the bill after completing the whole case. It will take couple of days. By increasing the amount of cases, we will receive lot of e-mails. For cutting down the amount of e-mails, please put it together and send it on 25th per month, not per case. Your cooperation is deeply appreciated.
The attachment is just for your reference.

The current operation pattern is that list of bills for the case will not be received until several days after the case has been processed.

However, due to the increase in number of cases, resulting in the too much number of letters received, we're hereby ordering to reduce the number of letters,

We hope that the lists of the bill will not be sent separately but focusing on the 25th of each month together to be sent, for our mutual convenience and service. 

The attachment are our other co-manufacturers' samples for your reference. Thank you for your thought and attention.

美國人習慣在你說的話中, 快速找出你要說的重點 太多不相關的細節會讓他們無法找到重點. 

另外, 他們會思考這和他有什麼關係, 像案件很多, 減少信件量, 不是他們關心的, 那是你的事.

另外, 要說服他們改變做事方事, 最好直接點出對他們有什麼好處. 

我想你要講的是第三, 四句, 一次送來. 對他們的好處是, 快速拿到貨款(?), 因為你們會一次處理. 

我會建議這樣寫, 希望有幫助和來得及.

Hi ___,

We have been receiving multiple, individual bills from you within a month. Bills sent separately actually increase our workload and slow down our payment to you. In order for you to receive payment as soon as possible, we'd suggest that you consolidate all bills/invoices and send them to us on 25th day of a month. In this way, we will be able to process your bills/invoices all at once and expedite our payment.

Attached are sample bills/invoices.

Thank you for your consideration,