Donald,
The only problem is that you have now zeroed your pistol for benchrest; what about zeroing it for shooting single handed and unsupported? The zero may well be in a totally different place.
I realise that you are quite new to 10m air shooting, so my advice would be to forget about zeroing at this stage. As long as the shots are all on the target that's all you need as you should be concentrating on producing groups that start to become consistent and show a decrease in size. By a "group" I mean 10 shots, any fewer is open to chance effects. Once you are shooing fairly consistent groups about the size of the aiming mark, then it's only a few clicks on the sights and a couple of groups to move the group centre roughly coincident with the centre of the target.
Another tip is to always use a backer target behind the target you are shooting at. Carefully align the front target with it every time. Then, at the end of a session you will have (say) 6 targets with 10 shot groups and one with a 60 shot group. This makes it much easier to assess where the majority of shots are going.
Forget about scoring targets, shoot groups. When you have achieved some degree of consistency then you can start to look at the score, but not before.
hope this helps,
Rutty