Tangie, the difference is the one you deleted was your own sim, the Devs mentioned it was game generated sims you cannot delete or sims they placed in hoods as those are "hardwired" what ever that means. They did not ever mention simmers created sims, but i have always just never deleted sims - just in case. I do know having dopplegangers can be a problem too, so I have gone to the extent of sending a sim I created to the town hall and changing their name to something like Jane or John Badsim, then I take and change their hair color, if it's a male maybe adding a beard, or taking away a beard, and giving them a whole new wardrobe - so the AI don't pitch a fit by having a duplicate in the hood. I then will move them into a house with a bunch of EA undesireables - filling the house to capacity and usually the game will eventually see things my way and move the whole household to Oblivion or where ever it sends the ones that leave. Other than that, I just tend to ignor them as muc h as possible. Also if they have a job, make them quit before you move them to the undesirable household.
I have had quite a bit of luck getting rid of them like that eventually. That way I don't have to worry about whether or not they will mess up the game.
