Your reply prompted me to look at my books and charts to refresh my memory,you'll get old one day.
The proviso as you say is that all MATZ contain an ATZ where you must not fly below 2000' without permission.
Anyway I always call a MATZ if I'm anywhere at all near them!
On the charts,the MATZ is shown with a C in front ie,CMATZ,why is that?
Lister
PS- I expect you are tucked up in bed now!