How to count the "10 calendar days out of time"

I know this probaly sounds like a strange question but can someone please explain how to count the 10 days which an application is out of time by. My reason for asking is because I want to know if I am a caseworker will use discretion to grant my ILR.

I first came into the country as a student in September 2000; application expired on 30 September 2001. My SAR shows that the application was raised on 11 October 2001 and granted on 5th December 2001. I remember sending it late because I was waiting for a letter fron my university by am not sure when I sent it . All my other applications were in time.

Now I can wait until December 2011 to apply for ILD but my work permit expires in October 2011 so I will have to extend then apply for ILR which I want to avoid. Any advice on how the 10days period is counted will be greatly appreciated. Thank you in advance.