It tells me that 'the sound in your head' is changing, which is very common as we mature and learn. Whatever sound you hold as ideal, you subconsciously find ways to get it. You can change mouthpieces, horns, reeds or anything else and you will always strive for the same results without realizing it. This is very like our voice, in that it can be recognized by those who know you, regardless of the gear you're using or the kind of music you're playing. The other half of it is your 'style', which is most always hand-in-hand with your sound. A core style has a core sound. Its hard to change one without changing the other.