It adds the point of asking where the figure of "at least $50" originated. My question was who introduced it, and your reply began "because".
Originally, I was suggesting that the dock and controller, as well as associated costs, would increase the price, and therefore could potentially push it beyond £200. You said "it doesn't" (I'm assuming you meant it wouldn't).
Then, when picked up on your defintive assertion, your reply was to introduce the figure of "at least $50" as a threshold for the price increase, hence my question. No one else mentioned that amount, and it seems like when pushed on whether the price could be bumped due to more items being manufactured and packaged, rather than simply accept that prospect as a mere possibility, you began retrofitting your argument around an arbitrary amount you'd decided upon.
As I said before, I'm happy to agree to disagree, but stating things as definite seems presumptuous.