If you've seen only four edits, but felt that any of, or all four were worthy of being considered for FEOTY based on technical editing quality, narrative alteration and overall enjoyment, then your votes are valid and worth while. Just as voting for it can be the critical factor, so can NOT voting.
If the edit sucked or didn't do anything for you then by all means, do not vote, but if any of those four blew you away or made you say to yourself "Self, that was an awesome edit, I truly enjoyed it and glad so-and-so made it" then a vote is entirely fair. This is not a scientific poll, it is one where the community indicates the edits which they feel were worth of consideration.
And also, that slim margin you noted is the reason the Academy gets two wild-card selections. If after the final 10 are decided by vote there are a 2 edits which they feel were truly deserving but for whatever reason didn't get the needed votes, they can still include them in that first round.
Ultimately, as a sage Jedi once advised, "you must do what you feel is right, of course." But please consider that such circumstances were considered when the nomination process was created.
And everyone, PLEASE VOTE!!