What the heck is PRE certified autos,? and what is it doing in the Certified category

in my search for an auto (Nissan Pathfinder)  in Car gurus , I checked the box CERTFIED - Pre owned and  and came up with vehicles from the Auto Barn Nissan  in Evanston, Illinois   , So I took a drive, WHICH was  an hour away to look at them , To my surprise  no cars at their lot are CERTIFIED  but they are Called PRE- CERTIFIED and it will cost extra to certify them and when i asked how much  the sales rep could not specify a set price. He tells me each car is different, What a crock of S#@& ,
so Car gurus is wrong to list them in the CERTIFIED PRE OWNED group , it would of saved me two hours of time and gas cost