The reference refers to reference tone at -20
so add 30 secs of 1K tone at -20 at the head.
Make sure nothing peaks higher than -9
That gives you an 11db range so try to work towards the top of that without peaking but keeping a good balance.
Ads are very often fairly highly compressed so appear "louder" even though they dont peak above -9
That may be why yours sounded relatively quieter.
Ideally you need some PPM meters to get this totally correct.
best wishes
Neil
http://www.patience.tv