As far as I understand, the whole pre-sale stage is divided into three stages, and why was this necessary? Why not make one pre-sale token and that's it?
Most likely this is due to some marketing features of the network, perhaps such an approach more actively encourages early investors.
As well as the terms of pre-sales are very tight, that is, all of our stages last for a rather short amount of time, if I'm not mistaken.