The changes involved in adapting a generic mammalian template into a whale are certainly not all simple, independent, single-letter changes.
Lee Spetner says of convergent evolution that it explains nothing but is simply a case of “giving a name to our ignorance.”
Two ears provide the ability for mammals to tell the direction of sound, involving multiple finely tuned mechanisms.
Surely no objective scientist would find evidence for evolution in nature’s echolocation designs. Would they?