Indeed, your take off charts/regulated take off graphs (or whatever your aircraft type calls them) will probably give you a mid-range V1 for whatever weight you are using. In reality, you have a range of V1s to use - providing you are not field length limited (i.e Vstop=Vgo). You may have some sort of procedure for calculating this range from the quick graph/tables. If you have, the choice of which you use is yours.
The mid V1 gives you a safety margin either side of Vgo and Vstop. The high or low V1 gives you less margin for error, but gives you the choice of taking your emergency airborne or not.
In a small turboprop aircraft, you will probably prefer to stop and deal with the problem on the ground. But in a max weight 747 after an engine failure, you may prefer to get the aircraft airborne on three (which it is perfectly capable of doing providing the failure happened past Vgo) and deal with the problem in the air, rather than deal with possible brake fires and an evacuation of 450 frightened people after a high speed abort.
It's a captaincy decision!.
[This message has been edited by Dan Winterland (edited 21 June 2001).]
[This message has been edited by Dan Winterland (edited 21 June 2001).]