Learn English – A comma before “using”

Punctuation is a matter of style and preference and it largely depends on which style book you or your editor use. However, using a comma is not as much confusing as other punctuation marks.

According to the linked Commas: Quick Rules by Purdue University:

Use commas after introductory a) clauses, b) phrases, or c) words that come before the main clause... Common introductory words that should be followed by a comma include yes, however, well.

1. The word yes is an interjection and it is usually placed at the beginning of a sentence. It could be considered as a word that come before the main clause which requires a comma.

Use a comma near the end of a sentence to separate contrasted coordinate elements or to indicate a distinct pause or shift.

2. isn't he in the sentence is called a tag question which could be considered as one of contrasted coordinate elements. Therefore, a comma is required before the tag question.

The truth about commas is that all the rules are just guidelines to help structure your sentences for readability. The purpose of the comma is to simulate the pause that would appear in the sentence if spoken. It's never required but it often helps.

In this case the comma is most frequently used because a speaker would pause before "although" to indicate a change in the direction of the sentence. For example:

I really love a good steak, but my doctor says I have to cut back on eating red meat.

In a similar way, a speaker would pause to separate the things in a list:

Is there anything in the world better than good wine, good friends, and good conversation?

Anyway, the rule you quote is a nice starting guide, but I wouldn't take it as gospel.