Usually, abilities of a class that talk about level refer to your level in that class.
If maneuvers known were based at all on your IL instead of your level in a given initiating class, I'd agree with you. However, since your IL only determines what you maximum maneuver level is, not how many you know, and since the gaining of maneuvers known is a class feature talks about your level without stating that its referring to anything other than the default level in that context (class level), I'm pretty sure the trick still works.