Activity - Delegated By Feature and Access Levels

Hi All,

   I need some clarification on the activity 'delegated by' behaviour. I have a role which has "Read/Edit" for activi for both owner and default access profile for activity. When I login as that role and create an activity (owner is me) and try top delete it system does not allow me to do because of my owner access profile.

How ever when I try to change the ownership of the same activity to some one else, I am able to delete it though my default access profile has only "Read/Edit". The delegation feature seems to give delete access to activities when I change ownership.