So as of Dec 31st, 2011, and despite 49 promotions in 2011, you're saying there were more than 49 promotions in 2011, because of their seniority numbers, right?
The variables are included in 1600/49, because those 49 are the end result in 2011.
Repeat: 32.6 is the current time to command for a new joiner as of right now, until the next promotion or the next variable or factor changes, all of which can change the rate either way.
Repeat: 32.6 is not the current rate for someone who joined in 2001-2010, or who will join in 2012 and beyond.