Most airfields I operate out of have runways which offer the option of Improved Climb performance using Improved Speeds.
Oft times, were I to elect to use this method to get airborne (for whatever reason), I might increase my V1 by anything up to 30kts.
Executing an RTO, for instance, at PRG off R/W 24, using Improved Speeds, allows me to reject a T/O at a speed far in excess of V2 using Normal Speeds!
There seems to be an additional margin here to be exploited which is well worth bearing in mind when considering a reject using Normal Speeds...