Math time!
So for the sake of argument let's say KOF13 sold 400K copies world wide. It would be fair to say that about a quarter of the people who bought the game also bought at least one DLC character. It would seem about right all things considered. So that's about 160K people buying DLC which would be about $800K for SNKP, but don't forget taxes and half of it goes to Microsoft and Sony. So they would make about $400K off of DLC so far. Not bad for characters that were already completed and on the disc...
So, based on everything I've read it would seem SNKP have about 12-20 people actively working on creating the sprites. I'm going to play it safe and say that the typical Japanese developer would be making maybe $14 Yen an hour with bonus pay if the game does well (which is typical in America). So $14 an hour, 40 hour work week for let's say 20 people would be about $11,200 per week, so $44,800 in a month. This is before taxes btw.
In a year's time after the release of the console version of 12 and the arcade release of 13, nine new characters were added (I'm counting Mature and Elizabeth from the 12 Console release). It would be easy to say to say that roughly 20 people working 40 hours a week could produce a complete character in about a month and a half but from what I've read it seems that it's usually 2-3 employees that work on a single character at a time. Without knowing for sure the ins and outs of creating high res 2D sprites I can't really tell how long it takes to create a complete character. So for the sake of argument a year's time would roughly equal 9 characters and 6 months would equal 4.
But the 6 months = 4 characters I really don't know how that can work out because that is including creating a brand new game with brand new mechanics... So let's say it would take somewhere between 3-6 months to create anywhere between 3-6 new characters. I think this is a reasonable expectation.
Okay, so $44,800 per month to pay 20 employees (not counting bonuses) X 6 months of work =$268K roughly speaking. End result being 6 new characters, now they could go $5 a piece or $20 for the set. Roughly a quarter of the people will buy the full set. I'm thinking roughly $3.2 million profit minus somewhere around 250-300K in development equals 2.9 Mil then of course Sony/Microsoft gets half of that DLC so it quickly becomes 1.45 Million in profit. Perhaps more or less, they could make even more by selling each character for $5.
Either way you look at it the profit margin isn't that huge. I would expect SNKP to be as cheap as possible and finish up Adel and whoever else was partially complete and do another headswap or EX character. All timed to be released around Evo.