I tested it with a 10x3x5 = 150 inside room cellar, which does not deem to work. Then I tried with 150 whole volume with the same dimensions and it also did not give any cellar benefits. I then tried with an inside of 7x3x7 = 147 which worked. Then I did 9x3x5 which also worked.
So my conclusion is that the rules in the wiki are absolutely bad wording and the actual rules seem different.