Hi ritter66, no-one replying, so here goes: you are right, you can use either of your versions and the meaning is the same.
Note, however, that the sentence (Later,) she insisted that the room was cleaned before we arrived as a standalone (i.e. without further context) is ambiguous. This is because of the two different meanings of "insist" - (1) to say firmly that something is true, and (2) to demand that something (should) happen. The ambiguity wouldn't arise with "said", for example.
The sense in which I understood it on first reading is this: She insisted that the room was cleaned before we arrived = she insisted that the room be cleaned before we arrived = she insisted on the room being cleaned before we arrived. The meaning is the same in all three: she wanted the room to be cleaned before we arrived.
For it to mean the same as the had been cleaned version, the intended sense is obviously she said the room was/had been cleaned before we arrived (even though there was dust on the table, cobwebs on the walls and rubbish in the bin ...).
Thank you very much for, as always, very informative post.
I wasn´t sure if "was" was possible because of the indirect speech "she said". It made me little worried what´s stronger. Is it the "before" or the fact that it is the "indirect speech" - where, in this case, I would expect the past perfect tense only.
Hmm, I don't feel any difference (or preference) between the meaning of "she said/insisted the room was cleaned before we arrived" and "she said/insisted the room had been cleaned before we arrived", so it's difficult to say which element - "before" or the reported speech tense shift requirement - "triggers" the "had been".
I looked around on grammar sites for the use of the past perfect (or pluperfect) and they all say, of course, that it describes one action (here "room cleaned") that took place before another (here "we arrived"). However I wasn't able to find anything that could explain what actually "triggers" the past perfect, in other words what makes the past perfect necessary and rules out the simple past. I have a general feeling that learners of English worry too much about this. If we have two actions (or states) and we know one happened before the other, they tend to think the earlier action (or state) must be described with the past perfect, but it's not so. They can both be described with the simple past as two actions in the past.
She said the room was/had been cleaned before we arrived.
(She said) The walls were/had been blue before they were repainted green.
(She said) She learned/had learned (to play) the piano before she learned the flute.
Ok, this is interesting. Englishismypassion - What do you think about the fact that in terms of how the indirect speech works there should be past perfect? How come that BEFORE plays the main role here and not the indirect speech "rule". I would like to know what makes one of the two "rules" stronger. Any ideas?