That website is way way off when it comes to next estimated difficulty.
http://bitcoinwisdom.com/bitcoin/difficultyThat one is way more accurate, and adjusts every so many blocks.
Our longterm average increase from the genesis block is 15.42% per adjustment. For easy math, lets say 15.42% every 2 weeks, thats 30.82% increase every month.
The increases as of the past year have been greater than this though. Reinvesting the 35% they are, will have them barely keeping up with difficulty, however, I do believe that it will have to level off eventually. I have no clue how large the network will be, but the larger the # the more it will take to push it higher.
If the site you mention, which I know nothing about, is accurate, then this does present a real problem. Using a long term average is not useful for prediction of next month, but using data from Nov and Dec at the site you mention we can expect an adjustment per month of 40%+. That would indicate a real-value loss of 20%+ per month, and these values do compound over time.
While I think it is unrealistic for us to pursue a 100% compensation arrangement, including the fact that we do not know the details of that contract as rdyoung mentions, I do think we should pursue protection from loss of real value. Perhaps we can argue for treatment only half as good as this other person received, obtaining 50% compensation.
While I do not think any renegotiation will happen realistically, and while I think PETA is a good value at .05 regardless, as I said before I would be all the more pleased if we can leverage this situation into an improved deal.