Yeah, definitely. Significant voice changes among AP/AR contents are certainly quite rare. I guess, if you think about it, shifting the voice tone from young to mature back and forth instantly wouldn't exactly be an easy thing for the voice actors to do. I imagine it can be a bit complicated and might also put some strain on the vocal cord in order to pull if off smoothly.
I am assuming you've seen and heard these ones already?
They are some of the decent attempts I've seen so far among the media.
https://www.youtube.com/watch?v=UjMg4uPdoNA (17:46)
https://www.youtube.com/watch?v=9wdet1d5nvw
https://www.youtube.com/watch?v=yKZFP55gpHI (4:41, 9:47)
https://www.youtube.com/watch?v=b8SzhdCdaGk (5:52)
https://www.youtube.com/watch?v=BGC4...890DB1&index=1