Comparing to Jade shield:
5
for 1 DR/immaterial/reflective (unupped)
7
for 2 DR/immaterial/reflective (upped)
A-Guard
4
+ 1 turn delay for 1DR/immaterial/reflective (unupped) <- might be balanced
5
+ 1 turn delay for 2DR/immaterial/ reflective (upped) <- a little too cheap.
I might increase the cost on aetheric shield if you want to keep this format. otherwise id suggest some kind of upkeep if you wanted it to be a cheap shield.