The "simplification" misses much of the point of yield management, from both the airline and the passenger points of view. Not every flight has the same sales pattern. Coach seats from the continental U.S. to Hawaii tend to be occupied by people who have planned the trip well in advance. Business class seats to London tend to be occupied far closer to travel time. The reasons are simple: last-minute business trips are common, but last-minute vacations are not. Yield management software uses the history of each specific flight on that day of the week, taking holidays and all the rest into account, to figure out how likely it is that X paying passengers will show up between then and departure.

Trying to pick fixed parameters like "6 seats still unsold a week before" imposes a regularity that simply does not reflect the real world. Sometimes having six seats available a week before means five will almost certainly go unused. Other times that same combination means the flight will probably be oversold. Yield management software knows which is which.

I also agree with prior posters that this isn't a simplification. I have a Ph.D. from MIT, have actually been a rocket scientist (control systems for lunar missions) and understand FF programs pretty well, but I found it hard difficult to decipher. Yes, I could figure it out, but let's remember the KISS* principle!
___________________________
Keep It Simple, Stupid.