The 330M figure was quoted over 3 years, not one year. For instance, were total sales last year, world wide $100M? Problem with estimating a TAM based on gov. budgets/replacement cycles is: terror subsides then sales down turn, terror rises then sales upturn.
The $330M figure I use is for 3 years. And I use $162M as IMSC's capture. Seems real to me.