It's complicated at first but a very good system. You have in fact pretty well got the hang of it, but not quite.
It isn't a choice. If you haven't seen
this page have a go at it with any browser except Internet Explorer, the calculator/estimator doesn't work in that. It's good for seeing different combinations and working out ones it doesn't actually have itself.
I gather you are on 21CN or FTTC/FTTP, not 20CN.
Let's deal with your second question first - that's easy. You would indeed have used up your quota (if the days were all Mon-Fri). You wouldn't be
stopped from downloading but you would be eating into the following months quota because of the carry-forward of over/under-use system. Unless you buy some extra, I'm not quite sure if/how you can do that.
Now the first question - looking at the page I linked to. Open it if you can while you are reading this.
1GB peak takes 0.8 units. Similarly 2GB takes 1.6 units. So 0.4GB take 0.32 units. 2.4GB as you specify = 1.92 units. You therefore have 0.08 units left, giving 8GB off-peak or 80GB night-time.
Similarly you can do different combinations of how you would use the 0.08. So 4GB off-peak and 40GB night-time.
Any clearer?
Edited by RobertoS (Wed 06-Jan-10 20:19:53)