Agents being anything other than agents at the same time has a tendancy to be a conflict of interest. It often means that the agent can't support themselves as an agent and uses other means (usually in some sort of paid services). That's not the kind of agent you want. If this agency is taking payment for editing, that's a red flag. If they're referring to editors as in that they help brush up their clients' work for submission, which I don't believe is too uncommon amongst legit agents, then it's just a confusing thing to state on their website.
Either way, it would be nice to have some clarification from the agency itself.