Chris goes on to say that another reason, which may be beyond the scope of Hannah's question, is that the increase in costs will be small.

The expression “beyond the scope” (scope) is a little bit like the expression “off topic,” which was discussed in an earlier lesson.

“Beyond the scope of something” means not related to what is being discussed.

Portuguese vocabulary, for example, is beyond the scope of this lesson, because it's about English vocabulary.

Chris means that one of his reasons for wanting to offer the product in more colors is that it will not increase costs very much, but he thinks that cost reduction isn't related to Hannah's original question, so he says it's “beyond the scope” of her question.

Then he asks, “Have I answered your question?” This is a polite thing to ask after answering a difficult question, because it lets the other person ask for more information - ask additional questions if he or she wants to.

Shawn speaks next by saying “Yes, certainly, Chris.”

“Certainly” (certainly) means definitely, without any doubt, for sure.

Shawn is saying that Chris entirely, or completely, answered Hannah's questions.

I certainly hope that you understand what this new word “certainly” means - for sure, without any doubt, definitely.