As part of the compromise deal, UKAD withdrew a charge against Tyson Fury of failure to provide a sample in September 2016.
UKAD chief executive Nicole Sapstead explained the delay over charging the Furys was a result of the complexities of proving nandrolone abuse, but denied UKAD had taken the easy option in reaching a compromise.
"It's a really complicated case and our policy allows us to do what we've done. We haven't broken any of our rules," Sapstead said.
"This isn't about resources. We have thrown an unprecedented amount of resources at this and have used very eminent and successful lawyers.
"We were prepared to continue with this case no matter what the cost, but in taking in everything into consideration, the money element did have to be one side of it. But it was not the full reason.
"Nandrolone carries a four-year sanction, which was our start point. Their starting point was they should get nothing and both sides produced evidence for their position so that's why we arrived at the compromise.
"It was not straightforward at all and there were some issues over delays over issuing the charges on our part due to the nature of nandrolone and that had to be factored into the overall picture."
The British Boxing Board of Control agreed to the resolution of these proceedings on the basis of backdated two-year bans.
Tyson Fury's successful WBO international title defence against Romanian Christian Hammer is scratched from his record as a result of the failed test.
That fight took place on February 28, 2015 at the O2 in London, and was his last fight before tackling Klitschko in Dusseldorf.
Hughie Fury, 23, could face Dillian Whyte early in the new year, with the pair discussing a possible February 3 fight in London.