My 3rd time of trying to phrase this question, please bear with me

I need to use autosave in Project 2010 but without overwriting the current programme. I do a lot of "what if" scenarios - sequencing asphalt laying etc, where other tasks have an effect, but that it may not become apparent until a complete what if.. has been completed. This means that I end up halfway through and autosave kicks in, destroying the main prog.

Is it possible to convince it to save the programme in a different location? I have set locatons, but this seems only to affect the initial location- if I have a programme that is elsewhere, it will save there. I save as I go through a sequence, but it can take 2 or 3 hours for a change, and losing a good sequence is ... annoying.

Thanks in advance