It's possible the purpose of wage benchmarking companies is to allow bosses to say they pay the 95th percentile - which is useful to be able to say, when someone at an all-hands Q&A asks about raises and bonuses.
Then the benchmarking company simply has to define 'comparable roles' broadly enough to give the customer the result they want.
It's thought by some that this is how CEO compensation has gone up so much: Corporate boards of directors have compensation committees, which are fed survey data about comp ranges; a comp committee will say, "We want our CEO's comp to be in the top quartile" — which, as time goes on, leads to an inexorable upward ratchet effect.
"I want to sell my water at the upper end and market it as a gourmet brand"
In fact if every company did pay at 95th percentile then I’d say it’s a good outcome. There’s a 5 percentile slack which is not too bad?