syntactic analysis - Is there a grammatical term for two "conditional" subordinate clauses being combined with "and"?

First off, sorry if my question is confusing. Or just plain wrong for what I am actually asking. But I am confused. I'm trying to figure out why there are no commas in two specific sentences. I don't think these sentences are wrong, but I want to understand why they are right. I am looking for a rule, but I lack the terminology to search for a rule.

Here are the sentences:

Because the topic covers several issues and because I was already working on one of the sub-topics for another article, I thought I’d answer the question in an article rather than in the comment section.

and

I’m going to focus on adverbial clauses since they’re usually the ones that cause the most problems and because the example in the reader’s question uses an adverbial clause.

They are both taken from this article: http://theeditorsblog.net/2014/07/30/commas-with-subordinate-clauses-a-readers-question/

The parts that, for some reason or other, confound me are in bold. Both are subordinate/dependent clauses, and both begin with a subordinate conjunction. At least, I believe that is the case.
But what do they turn into when the construction is done like the above? A "compound subordinate clause"? And why would there be a small voice in my head, asking me why there is no comma before the "and" in the bold parts of my quotes?

Additionally, would the same grammatical "state" (yes, I am obviously lacking terminology, I apologize) still apply if, in the first quote, the subordinate conjunction was not repeated? As in:

Because the topic covers several issues and I was already working on one of the sub-topics for another article, I thought I’d answer the question in an article rather than in the comment section.

And again I feel like there should be a comma here between "issues" and "and".

Someone please help me out here.

Thank you.