See though, I feel like the problem with googling something like that is it pulls up articles and people all describing interviewees for one certain type of job. Obviously you should follow the "conservative suit, pantyhose, closed toe shoes and for godsake straighten your hair you heathen" diatribe if you're applying to be a senior accountant or the CEO of Houghton Mifflin or something, but what about every other job?
I interviewed applicants for an internship with a small environmental advocacy group, and if someone had shown up in CEO wear, it would have been super weird. What about for a factory job, or a creative job. It's really not so cut-and-dry as all that. I wore the dress, with the cardigan. I don't think they minded. I did buy some lower heeled shoes though, because those felt a bit too fancy.
First off, I hope you get the job!
The standards that you'll find from that Google search apply more broadly than you might think. I take your point that if you are showing up to a job interview to be a server at a restaurant, or a ditch digger, or a community activist, the standard is not necessarily "conservative suit." But the concept of "wear a suit to an interview" applies much more widely than just for managerial positions and CEOs.
I agree that context does matter. If you know that everyone in the office sits around in shorts and a T-shirt then yeah, a full-out formal suit might not be as appropriate for an interview. But one rule of thumb that is useful for
any job is: dress better for the interview than you would normally dress on the job.
I recommended a suit because you said things like "office administrator," "large ... company," and "very formal-dress interview." Like other people have said, it's usually worse to be dressed too casually than it is to be dressed too formally. And if you show up wearing a suit and, to your horror, you've overdressed, you can at least take off the jacket (and if you're a guy, take off the tie). If you're underdressed, you're kind of screwed.
If in any doubt, dress up.