I tried to mean there that it seemed like it was the consistency of a portabella cap, as in, if one were to bite into it, maybe it would be a similar texture to button mushrooms or portabella mushrooms. And yes it does seem quite old. The bark of this tree and many others were grossly stripped (where giant chunks of bark were seemingly purposefully removed) so I imagine this fungus grew throughout the gap in that stripped bark. Maybe that could suggest it is more a result of how much bark was stripped instead of typical max growing sizes of particular species? I'm not sure. I'm 100% new to this (started a couple weeks ago) so I apologize if I'm not too helpful.
Thank you very much for the suggestions though, I'll search around and see if any of them lead me anywhere.