In the companies I worked it, engineers were at most at 3rd level support (mainly in places where the users were business experts and advanced computer users) or even the people 3rd level support calls when they can't sort the problem out.
Either way, the vast majority of support calls are filtered by lower support levels out before it gets to them.
Putting engineers as first line support sounds like a spectacularly bad idea, at multiple levels: they're far too expensive to waste doing that job, they generally tend to use expert terms rather than common terms so the users don't get them, what they see as "baseline computing know-how" that they expect users have is still well beyond the computing expertise of most people so all in all they tend to detest doing it.