As the nomination ballots for the 84th annual Academy Awards hit the mail on Dec. 27, voters are wondering about how the preferential system will work with this year’s rule changes.

When the Academy of Motion Picture Arts & Sciences decided in June to make the number of best picture nominees vary between five and 10, the announcement again brought up questions about how voting works and which films will benefit the most.

So, as a service to voters, Variety talked to Acad and PriceWaterhouseCoopers execs. But there’s no guarantee this will stop the head-scratching. The bottom line: Fill out all the slots on the ballot, but think carefully about the order you put them in.

It’s important to note that the basic system of voters ranking films in order of preference has been used in the nomination process since 1934. The only real noticeable difference this year is that no one will know how many films will be nominated until Jan. 24.

Academy COO Ric Robertson said keeping the number of nomination slots flexible made sense after looking with PwC at how the number would have varied over the last decade.

“We were able to see that some years we’d have five or six or maybe even 10,” Robertson explained. “That really sparked us to think that this could work, and it would be an interesting tweak of our rules.”

So how exactly does it all work?

PwC’s Rick Rosas, one of the people charged with tabulating the ballots for the company, breaks down the process into a series of very analog steps. (Keep in mind that all of the tabulation happens by hand in an undisclosed location over the course of a few weeks.)

The first step for PwC tabulators is to determine the minimum number of first-place votes any given film would require to secure a nomination; they do this by dividing the maximum number of slots plus one, i.e., 11, by the total number of ballots returned.

Then the ballots are sorted into piles based the number of No. 1 votes each film receives. Any film that already has that minimum number of votes is automatically on the list of nominees.

“We actually are pushing a lot of paper,” Rosas said with a laugh.

Conversely, a film with less than 1% of the vote is eliminated, according to Academy rules. The eliminated films’ ballots are then reallocated based on the No. 2 choice, assuming it hasn’t already secured a slot. If a ballot’s second choice is already nominated, the tabulators keep going down the list to ensure that a vote gets counted toward a film that needs it.

Further complicating matters, the system is designed to avoid letting any single film end up with a preponderance of votes. For that reason, if any film at this stage has a surplus of votes, or 10% more than what is needed to secure a slot, the second choice on those ballots are reallocated at a reduced value.

“We will reallocate all of the ballots for the film to the second-place choice, assuming the second place film hasn’t otherwise been nominated,” Rosas explains.

There could be any number of films that have secured a slot at this point, but this is where the change for this year comes into play:

“At this particular juncture, we will then determine the 5% threshold of all the outstanding votes. Meaning, if I have 6,000 votes out there, we’re going to look and say, what’s 5% of 6,000? It’s 300. All those films with 300 or more votes will be nominated, unless I have more than 10. If we have at least five, but less than 10, we’re done,” Rosas explained.

The real salient question for voters is, Does it make sense to fill out all of the slots on the ballot? Will those votes be counted? The answer is: Well, it depends.

“If they pick two films that they just love, but they’re kind of in the weeds, and those films get eliminated in the 1% round, then I have nowhere else to allocate that vote. It depends on their taste in movies, and how well it matches the taste of the Academy overall. The preferential system’s always been geared in favor of those voters who fill out a complete ballot, and it’s still the case now,” Rosas said.