if the third line showed a higher number then the set point i would think about replacing the drive. what your seeing is a true but false error with the software. it true because as you use hard drives (smaller drives and laptop because there moved when running). end up with small defects on the platters when the errors happen the drives firmware writes those spots out so your windows or aps wont use them. you cna google hard drive defect list..plist and glist.
for more info. when a drive is made the vendor makes a defects list of all the bad secotors on a drive and makes a plist that the firmware reads and knows where these defects are. the glist is a set size by the vendor so that the drive can have more bad spots and have them...