AOR date

[Lalehgol]

Hi everyone;
Recently I recognized that the AOR date at the bottom of my AOR letter is 20/04/2007 while I sent my documents in Jan 2008 and date of the AOR letter (top of the letter ) is 27 Feb 2008. I doubt if it is a typing error or not? if yes then I waned to know:
1) Is it required to inform the immigration office?
2) Can it cause delay on my immigration process?