Hi Rosy,
I've been mulling over the same question lately: when in 3rd person single POV, how much does the narrative need to be in that person's words?
Obviously (as has been illustrated by others in this thread) there are lots of different ways to do it, but personally I do this:
1. Dialogue obviously in that person's words - words they would say out loud.
2. Narrative in that person's thoughts, so you can't mention anything they can't see or perceive (I know you know this but am just being clear), and written in words they would use inside their heads. Words they would think in, but not necessarily words they would say.
I think this strategy is consistent and one of the many correct ways of doing it, and I also find it simple and pleasing.
If following this I would not describe her moving across the kitchen from the outside, so I wouldn't say that her face was red. I could say that her face felt hot, because she would know that. Because it's a pretty non-emotive thing (moving across kitchen) the narration would sound pretty neutral but would actually be her knowing she was moving across the kitchen.
I think most modern books are not written with omniscient narration and I personally dislike it and would neither write it or choose to read it. Perhaps that makes me narrow minded, but hey... I can live with that.
Am I talking about the same thing you're talking about or have I misconstrued your question?
And I'd add this, but I'm not so sure about this bit: I think real people have thoughts (about themselves and other things) that they would never describe in words out loud to others, so characters can too. And their thoughts can be in words they wouldn't use verbally, so long as they would understand the words, because when we think we don't necessarily think in words - well, I don't think we always do - and when we speak we often conform to the norms around us and actually don't use all the words we know. But they'd need to understand the concepts if they were thinking those things, so it would seem inappropriate to have a character thinking in words which were outside their sphere of experience.
Deb