iPhone 4S Mail app downloading vasts amounts of data

[Atlantean]

Since changing my iPhone 4 for a 4S I have noticed my data usage rocket on my new iPhone 4S. At first when I noticed this I did not know what was causing it so yesterday I downloaded an app to check which apps were causing this high data usage.

My iPhone is Jailbroken but I don't think this has any bearing on my problem as the data usage was high before I jailbroke the iPhone.

Today my iPhone downloaded 15 emails from my Spamarrest mail account since midnight which totaled 264k on the Spamarrest web site. However according to the app iNetUseage the mail app downloaded 27.45MB of data since midnight!

Something is seriously wrong with these figures! How can 15 basic emails amount to 27.45MB of data, not one had an attachment!

I have read of the Mail app checking for mail in a loop which caused high upload data usage but in my case the problem is with download usage.

I have "Push" switched on but this is for my iCloud mail account. I have not received any main from that account today. I have my other email account, the Spamarrest account set to fetch at 15 minute intervals. Would changing these settings help reduce data download usage?

 

[Atlantean]

I would appear that a standard text email is using 1.75MB of data to down load. - I did a test email last night where on the computer is sail 3K but when I looked at the counter on the iPhone it went up by 1.75MB. This morning I downloaded 5 regular emails which added 12.8MB of data to the counter

The "Push" and "Fetch" features don't seem to make a difference to the download amount!

What could be the cause of this does anyone know?