Your copy of the regs is correct - they haven't changed in years.
What tgrayson is referring to is the way the FAA interprets it. Officially.
If you head over to
http://fsims.faa.gov/PICResults.aspx?mode=EBookContents and drill down to Volume 2, Chapter 5, Section 11, you will find the following in paragraph 5-503:
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According to part 61, flight instructors who hold an “INSTRUMENT-AIRPLANE” rating only on their flight instructor certificate are authorized to give instrument flight instruction in single- and/or multiengine airplanes for instrument certification, provided they hold single- and/or multiengine ratings on their pilot certificate.
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Instructors with ratings limited to instrument may not give instrument flight instruction to students who do not hold category and class ratings in the aircraft used. This would be instruction for the addition of a rating that conveys other than instrument privileges.
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