Wingo wango, NO the cost benefit or deficit has not been clearly addressed. What we have had is some differing views on what happens. Interesting regarding the time issue, do students carry a stopwatch with them?
I don't think this is a cost issue, there are far more eaiser ways to fleece a student.
It therfore must be safety related and with that in mind I, as a professional, am interested why students are not allowed to go and fly touch and goes. Are they allowed to fly cross country? It seems to me that there could well be a falling down in training standards that need to be dealt with and fast.
Aviation is a pretty safe industry and flying is great fun, but you must always give it 100% of your attention or you will get bitten rather hard.