Was able to contact the Brand Ambassador for The Macallan. He is one of three in the US. Here is what he set me
When I was at the distillery in 2009, I asked Bob Dalgarno, the Master whisky maker the very same question that you asked me...
The Answer is: The age statement was removed from the Cask Strength in the US because some of the liquid in the bottle was younger than 10 years old. It is in fact a vatting of European Sherry casks between 8-12 years old. This is the unofficial time frame in the casks, and according to Bob, who is charged with ensuring the color, character and complexity and consistency of every bottle that has our label on it year after year, only non-age Cask strength is now sent to the US. You can still purchase Cask Strength 10 yr in other markets around the world.
I also got an answer back from an Marketing Assistant forThe Macallan
it doesn't carry an age statement as it varies in age from bottling to
bottling. Our whisky maker has complete freedom to select casks
according to their character rather than their age to achieve the
flavour and nose that is required for this whisky. On average, it would
be around a 12 years old whisky but it can vary between 10 to 15 years
from bottling to bottling.