You don't need to rely on chance to get the Eevee evolution that you want. Change the name of your Eevee to:
Rainer if you want a Vaporeon.
Sparky if you want a Jolteon.
Pyro if you want a Flareon.
The insinuation someone this high level doesn't know that is pretty funny. That trick only works once. You can't get infinite Vaporeons from naming the Eevee Rainer.
Need help? Creati0n says: still my favorite. <3 I sacrificed my firstborn for this great human being to join (M) ~R Just Use Thunder!