This has been a point of arguement between me and another storyteller: Can a vampire starting with (e.g.) 4 dots in Domination use the lower level power (i.e. 2 dots Mesmerise)?
To me it's pretty obvious that if you can turn someone into a slave (4 dots Dominate) you can just as easily give them a simple order (1 dot), but his counter-argument is that this is true only if you've upgraded your discipline (so, if you started at 2 dots and upgraded it later to 3, you would have access to 2- and 3-dot discipline, but not to level 1).
To be fair I can't find any written support for either side.
Let me ponder on this discussion bit more: If we'd assume that fledgling vampire has to (even briefly) train/concentrate to gain access to higher than first level of discipline, this is akin to learning any other skill i .e. riding a bike: At 1 dot you can ride with training wheels, at 2 you can drive in most condition, at 5 you could do a 360 flips during blizzard. But having high level skill wouldn't suddenly made you forget how to ride on straight road.
But then from the other hand you became vampire instantly - there was no situation where you were "just a little bit undead" and such skills as blood drinking you learn instantly. Same principle works with other vampiric properties i.e. clan flaws - when turned to Malkavian you almost instantly get insane, then why such principle shouldn't apply to discipline? Bam! You got hit in the head, bitten and now you can make people fear you (Presence 2) but making them attracted to you (Presence 1) is bit beyond your grasp.