If you create a poll then after votes have been made, you add another option anywhere but at the bottom of the list. So lets say at the top, the new option takes the votes of the option that was at the top before and all the other votes move up so the option at the bottom now has 0 votes.

Like this:

Before

Option 1 - 5 votes
Option 2 - 1 vote

After

New Option - 5 votes
Option 1 - 1 vote
Option 2 - 0 votes

I hope this makes sense.