I’ve never seen data that would give a basis. The above cited text doesn’t, as the stated usages are unequal. It’s possible that the original source might cite references that might have the data, or other studies might have it, or it could be that the comparisons are just unequal and that’s all there is to it.
There has been fuss about all kinds of things that hasn’t been merited. For example, remember methandriol dipropionate? You used to have to take that to “sensitive your androgen receptors,” don’cha know. Of course that was totally bogus: the stuff is worse than useless.
Or how about all the fuss that continues to this day about SHBG? (Nope, I won’t go into it again. One could use Google, limit the search to this site, and to my name and to SHBG.)
Not that boldenone is an ineffective anabolic. Back when there was no means to control aromatization, what with Deca having the adverse side effects it does and therefore it always being desired to limit the dose and often being desired to not use it at all, and trenbolone generally not being available, it was a good thing to include in a cycle. These days, no need. But if one happens to have a bottle, or can get it easily and cheaply or whatever, fine. Just don’t expect magic properties.