Looking at the example given by R&R for RES:
1-3"
2-4"
2-5"
Notice that 2-3" fish fit into all three categories. You could pay anywhere from .50 to .80 cents apiece for the same RES, depending upon which size class you specify.
Not really....1-3" will average 2".....2-4" will be mostly 3" and 2-5" will be mostly 3.5" and bigger with very few smaller ones under 3".
The ranges shown are almost certainly all YOY fingerlings, with the larger ones being shooters.