I believe the key word in your bolded statement is "usually." That implies there may be exceptions to this advice. However, there are no qualifiers around "Each undergraduate status should consist of approximately 27-35 hours." So, that range applies to everyone. Note that immediately prior to your quote is stated: "If the Year in School selected greatly exceeds the ranges specified below, AMCAS may reassign statuses." I should also point out that nowhere in the manual do I believe that it says "if you are a full-time, continuously-enrolled student, list your year exactly as it appears on your transcript" (emphasis mine). The fact that AMCAS provides you information on calculating your Year in School implies that your transcript's indication of your year in school is not the same as AMCAS's Year in School.
For situations where you may have more credits than the typical undergrad (upper bound: 35 x 4 = 140), we can look to the table previously mentioned for insight as to what should be done in that case. The fact that Senior status gets 91+ credits implies that, all other things being equal, the Freshman, Sophomore, and Junior statuses should be kept to approximately 30 credits each and no more, and that the Senior status receives all excess credits.
I don't believe I can elaborate on my rationale any more than I already have. If there are continued disagreements with my interpretation, I highly recommend that rather than continue the discussion here, seek advice from the authoritative body, AMCAS, directly. While I don't intend to steer anyone wrong here, the best I can do is say "these are the manual's instructions and this is what I interpret them to mean." If you call up AMCAS and say "the advice you were given is horse-dung," then please come back and post. (If anyone reading has direct experience with this, that would be excellent as well. I had a typical undergrad transcript.) I would be happily shown to be wrong in that case, so that we can give more definitive help to people in the future.