Makes sense. But won't HKS just lie depending on which way it makes it look like she injected herself? I wonder whether anyone else witnessed the injections besides ANS and HKS that could provide a history...
Well there are some factors here...
Who saw her that morning - what was her condition that morning - what was her condition the evening before - who saw her the evening before.
Who's name was the Demerol in? (so far it sounds like it was in someones name that was not Anna's or any of Anna's aliases.)
If it was in Howard's name why was Howard injecting her with large doses of HIS Demerol?