It works to me at least. Currently I have one /NGU0-/NGQ0 spread position + one outright /NGU0 position (Total 3 /NG contracts). AMP charged me $2050 for margin. I don't know how this number came out but I don't complain. (Actually I thought it would be $2700 - $1000 for spread and $1700 for outright.) This was also confirmed by AMP by email.