By regular traditional enclosure standards, that's an acceptable size for anything other than a truly big BP (6 feet); those recommendations tend to be L x W of the cage = length of the snake.
By "bioactive" standards and reasonable practices, not so much. Even on a naturalistic enclosure mindset that could be a little small. That could be part of the difference in recommendations.
I'm glad you said that...I have no experience with bioactive enclosures, but I was thinking they might need more room.
Rudeness is the weak man's imitation of strength. Eric Hoffer(1902 - 1983)
“The greatness of a nation and its moral progress can be judged by the way its animals are treated.” ~ Gandhi