Well to be honest this isnt a 15 year old tier set. This is something I made up with some input from JMC and Justin for Smogon.
I am pretty sure we know that Cloyster is used more than Persian. I mean this is from compiled anecdotal evidence, but really, in this situation I have a great deal of faith in it. I mean, lets be honest, is anyone really questioning the accuracy?
If Jolteon is seeing a lot of use, that would surprise me, but it could well be that it is..
But the reason for this basically is that I just played RBY UU and it sucked. I might play RBY UU a couple of times in the future as well. Tampering with this is not like tampering with RBY OU because to be honest, nobody ever played RBY UU. There are probably historical uu tiers that have seen more usage than the Smogon one. This tier list was made after Advanced was out.
There is definitely more balance between Jolteon and Raichu than there is between Electabuzz and Electrode.
Have a nice day.