I experience the same/more problems in this way.

File uploads below post_max_size and file_max_size work without any problems.

If the filesize is bigger than one of them, PHP does not accept the file, but file uploading continues until the "real" end of the file regardless of the limit settings (even of input_max_time)

Thank you for this bug report. To properly diagnose the problem, we
need a short but complete example script to be able to reproduce
this bug ourselves. 

A proper reproducing script starts with <?php and ends with ?>,
is max. 10-20 lines long and does not require any external 
resources such as databases, etc. If the script requires a 
database to demonstrate the issue, please make sure it creates 
all necessary tables, stored procedures etc.

Please avoid embedding huge scripts into the report.

The following code (consisting mostly of the example from the php docs) should only allow 300kB files to be uploaded resulting in an UPLOAD_ERR_FORM_SIZE. If you dismiss the hidden field, it should produce an UPLOAD_ERR_INI_SIZE. Emergency stop should be after max_input_time.

My Values are:
upload_max_size: 8M
post_max_size: 8M
max_input_time: 60

Reality shows, that a possibly created tmp File stops growing after reaching upload_max_size and is deleted, but upload continues even after 60s (watch with iptraf or something like this).

<?
print "upload_max_size: ".ini_get("upload_max_filesize")."<br>\n";
print "post_max_size: ".ini_get("post_max_size")."<br>\n";
print "max_input_time: ".ini_get("max_input_time")."<br><br>\n";

print '<form enctype="multipart/form-data" action="'.$_SERVER['PHP_SELF'].'" method="POST">
    <input type="hidden" name="MAX_FILE_SIZE" value="300000" />
    Send this file: <input name="userfile" type="file" />
    <input type="submit" value="Send File" />
</form>';

if (isset($_FILES["userfile"]))
{
	var_dump($_FILES);
}
?>

That is because your client (browser) keeps uploading the file.
There is nothing PHP can do about it except ignoring it.