length violation: POST data vs request

im doing some tests with a html page / php script with which i can upload a file. when configured on a low value at File Types > php > Request Length / POST Data Length both these violations trigger: Illegal POST data length /Illegal request length.

 

 

am i correct in assuming that the request length is about the whole request and the POST data only about the send POST data? would this usually mean that you need to set both on the same allowed size? request perhaps a little higher because of the headers?