Samsung sph-a680

I recently purchased this model(samsung sph-a680) and I was curious about the "Last Call" feature. Is anyone familiar with this? Sometimes it's accurate, but sometimes it's not. For example...sometimes it shows the last incoming name/number, but below it shows the last previous outgoing call time and date. Is my phone messed up already or is this just the way that feature works on this phone? The last phone I had(samsung sph-n370) told me exactly the number, time and date of the last call whether it be incoming or outgoing. Any info. would be helpful from someone familiar with the features of this phone...