@homemadecandle:
That's an interesting theory, but Funimation did state that they wanted more episodes. If it was because Navaare was selling them it would be for different reasons.
Allow me to elaborate on my thought process here…
If negotiations and an agreement and payment was made on season 4 in a manner that would have allowed a release of season 4 consistent with the releases of the prior seasons (ie, the next set comes about 2.5-3 months later), then Navarre would have forked out 1 million plus for season 4 by the time s3v5 came out. (The math on that is based upon the ~10k per ep times 100+ eps for season 4. Someone correct me if I'm wrong on that, please.) Regardless of specific numbers, I think we all can agree that season 4 is going to (or for the optimists, has) cost a rather large chunk of change.
Navarre had FUNimation up for sale for a year at the time they sold it, which was listed as sold as of March 31st of this year. S3v5 was released on April 19th. If Navarre shelled out the money for season 4, they wouldn't have seen a dime of the profits on that, if the release timeline continued consistently. So negotiations were put on hold until after the sale was finalized. And when you add in the earthquake probably causing some delays, that would fit in with why we didn't get a definitive, "We're in negotiations" until only a few months ago.
At least, that's the only reasoning I can come up with as to why it wasn't acquired earlier, despite seeing the approach of s3v5.