I know it is no longer done this way, that is why I wrote "That was due to the fact that originally electors just voted for two people for president.
Let's look at the Constitution itself:
Originally electors voted for two people without specifying president or vice president: "The Electors shall meet in their respective States and vote by Ballot for two Persons, of whom one at least shall not be an Inhabitant of the same State with themselves."
The person with the second highest number of electors becomes VP :"The Person having the greatest Number of Votes shall be the President, if such Number be a majority of the whole Number of Electors appointed. In every Case, after the Choice of the President, the Person having the greatest Number of Votes of the Electors shall be the Vice President."
Because electors did not vote separately for president and vice president is the reason we elected a president from one party and a vice president from the other--Adams (71) and Jefferson (68) in 1796. In 1800 two members of the same party tied---Jefferson (73) and Burr (73). This was one of the reasons for the 12th Amendment. Founders did not anticipate the development of parties and candidates.