After getting your Trademark approved, what logo exactly is covered?

It is not clear to me what trademark you registered. Specifically, it is possible for you to register just your company name (a word mark without the logo) and get the registration approved by submitting a specimen as you have described it. When you received your registration certificate, it contained an image of your trademark and that image defines your registration. For purposes of my answer, I am assuming your registration matches your specimen. You should only use the circle R symbol on representation of your trademark that include everything contained in the registration as it appears in the registration. The Trademark Office treats little alterations as different trademarks. When renewing trademarks, I have had the Trademark Office reject specimens that have words in quotes, an added hyphen, an added space, and different shading within letters as well as relocated objects (e.g., logo relative to the words). If it doesn't match, just use a superscript TM. The superscript TM gives notice that you consider the mark to be your property, but does not identify the mark as registered. The circle R gives notice that you consider the mark to be your property and it is registered. If someone else were to use the variation on your registration as you described it, they would likely be found infringing, but that doesn't mean that you can declare it is registered if it doesn't match the registration. Good luck, Todd