Unexpected results using APC with the rfc 1867 feature to get progress

Hello, I made a simple form uploader that gets the progress of your upload using APC. While the file is being uploaded ajax requests are being made to the server to get the progress of the file being uploaded. The problem is that the extension is returning back numbers that don't make sense. The apc_fetch method is sometimes returning back a greater current than a greater total and sometimes returning back a smaller current number than it did earlier. I am running PHP 5.2.5 on Windows 2003 Server with Apache 2.2 and APC extension that comes with PHP 5.2.5 of course. Is this possibly a known issue? I noticed this issue on my windows setup but I also have a seperate setup running on openSuSE 10.3 and haven't experienced any weirdness like that. Please let me know if any of this is know. Thanks.