I think the best use of the term
would refer to the volatility in our ability to assess the composition. (But not volatility in the composition itself, which is the error)
Example: We have a six deck shoe with 100% penetration. Someone may say that the true count is more volatile in the last deck. We could possibly have a true count of +8 or more in the last deck. We could never have a true count of +8 in the first deck of the shoe. So we have more true count volatility near the end.
But the beginner does not realize the the first and last 52 cards of the shoe are substantially the same. The first 52 cards of the shoe has the same probability of having a +8 composition as the last. Any 52 card composition is equally likely anywhere in the shoe. We just would not know it because we don't have enough information... we haven't seen enough cards. So if we define volatility of true count simply as our increased ability to make more accurate predictions, then yes, the last 52 cards of the shoe has a much more volatile true count. We gain because we see opportunities that we did not see before. Not because more opportunities actually exist. This is why the edge for a flat betting basic strategy player would be the same, and his SD would be the same, in the first deck of the shoe or the last. (except where the cards run out and need to be reshuffled)
Those who are confused about the 1st and 3rd base issue don't realize the difference between the actual event and our ability to predict the event. They think that an increased ability to predict an outcome actually influences the probability of the outcome. A total illusion, like I said before. Seeing the cards that are dealt to the players between first and third only affects our ability to predict what third base will draw. It has absolutely no effect on what he actually will draw.