Teacher Discussion Forums

I have read in a book something like this:
1. "Ann works AT a publishing house." -
She is directly connected with the publishing job.
e.g. an editor
2. "Ann works IN a publishing house." -
Not directly connected with the publishing job.
e.g. a receptionist, security guard, etc.
Is it true?
Also, could we use 'company' or 'firm'
in place of 'house' in this case?
Thank you.

'Ann works at/for/in a publishing house': Why is the speaker always so vague? So grudging with the information? Maybe a grammarian has been "simply" trying to highlight a supposedly "interesting" difference through the use of strictly limited and thus always decontextualized sentences!

Ann works at/for/in a publishing house. (Yes, but which one?)
>Ann works at/for/*in Penguin Books. (Yes, but what's her job there? Oh, you could also say 'Ann works in publishing' - the industry, not that that would be very informative either - but now you've mentioned a specific company, I'd like to know what it is exactly that she does there, okay?).
>>Ann works as/is an editor at/for/*in Penguin Books.

(NB: 'Ann works in personnel at Penguin Books' is possible - a part of a whole).

'House' collocates with 'publishing', but other industries would use less specific nouns (such as, yes, 'company' or 'firm').