The use of the "Model of 1905, Xth change" terminology in a way parallels that of the screw count.
My observation has been that experienced collectors use it only for the time period where it is actually helpful, in this case until shortly after the 4th change, and don't thereafter.
Just like the number of screws, which (if actually counted correctly) are very helpful for specific models and time periods, but unnecessary for most, the model/change terminology tends to be over-used, and is best enjoyed in small doses.