Sender file content conversion

Hi Experts,

I have a small query.I am testing a file to file scenario in which, at the sender file channel in content conversion "Recordset per message " is set to 500.

So when I am sending file with records more than 500, its is correctly creating messages in sxmbmoni with 500 records per message.

But the files that is getting archived are getting appended with ".filepart" .

Is this normal functioning?I am not sure as I have never come across such interface,so just to confirm.

Thanks in advance.