Aamandani, it all still depends on the specific certification of the expanding on what i said above a little---
ONE WAY your to determine Vr= 1.10Vmu [as you wrote] when tail grounding isn't a factor and 1.05Vmu when it is but other criteria may apply and any one of the above minimum criteria previously stated may have been used to determine your V speeds....also Vr has to assure that under limiting critical cases that V2 is achieved OEI---at the correct fence or screen height---
---However for economic/safety considerations when a limiting scenario isn't encountered flexibilty is available in the V speed selection allowing a greater flexibilty in operations depending on specific company goals
and this particular discussion can really flare up
