Revoltech Magnus Questions

Just got my Revoltech magnus today. GREAT FIGURE! But while I was fiddling with him one of the post on the thighs revolver joint broke off inside the waist. (Man was I pissed). Well thanks to my kitbash parades I got the stub out and put the white revolvers in. Which leads me to my Questions.
Why does Magnus come with more joints?
Why are some of them Double jointed? (Obviously for more articulation, but why? the single revolvers that he come with allow for the best poses in a TF figure ever.)
And why White and not black like the existing joints?
Can the revolver joints be purchased seperatly? Or will I have to cast them?
And Finally, why doesn't Prime come with extra joints?
If any one can help me with the answers, thanks a bunch.
Why does Magnus come with more joints?
Why are some of them Double jointed? (Obviously for more articulation, but why? the single revolvers that he come with allow for the best poses in a TF figure ever.)
And why White and not black like the existing joints?
Can the revolver joints be purchased seperatly? Or will I have to cast them?
And Finally, why doesn't Prime come with extra joints?
If any one can help me with the answers, thanks a bunch.