It depends on what you do in the third season:
"A club that moves between the Premier League and Championship will be assessed in accordance with the permitted loss in the relevant divisions played in during the three-year period in question. For example, a club that had played two seasons in...
To all intents and purposes the rules came in this past season because, as you say, there was a one-off allowable loss of £13m which is the mean average loss per season allowable under the new rules.
You would hazard a guess that is why both Derby and Boro "went for it" somewhat.