All getting a bit pedantic here isn't it.
Just to throw my oar in here, in my view if you are on an IFR flight plan, then that is an IFR flight. What the actual met conditions are is irrelevant in my view. I personally haven't got a clue how much time I've spent in 'actual' IMC and to be honest don't really care either.
However, if you are logging IMC time whilst instructing in the open FIR on a VFR flight whilst in VMC (ie the student is under the hood but you are in good viz) then that is a bit naughty.
But as I said before, who's going to check?