Samsung SPH-A680 / VM-A680

I was curious as to how the Last Call feature works on this phone! I previously had a samsung sph-n370 phone and the last call feature on that phone worked perfectly(indicating the exact last incoming or outgoing call, time, date, etc... However, with this a680 phone, I find that the last call feature isn't very accurate. It seems to work most times with the last outgoing call. But when I receive an incoming call, it seems to indicate the name/number and airtime of the last incoming call, but the date and time of the call prior to the last call. I know this probably doesn't make much sense, but does anyone out there use this feature and if so can you please tell me how yours works? Is this feature messed up on my phone or what? Much appreciated!!