Some Gross wight charts or RTOWs offer the oportunity to operate with a range of V1 when taking off from a runway longer than needed.
V1 max will be limited by ASDA or TORA (if SWY not available)
V1 min will be limited by TODA or TORA (if CWY not available)
The bigger the diference between runway needed and available the wider the range.
Anyhow, V1 must comply with limitations regarding Vmcg and Vmbe.
Prior the take-off only ONE (not a range) V1 must be chosen.
A very nice explantion can be found on "Getting to grips with aircraft performance" from Airbus. Look at
SmartCockpit - Airline training guides, Aviation, Operations, Safety at Flight OPS/performance/ "Understanding V1 Range" from Boeing.
REGARDS.