The 4600 series matches the 9200 series for performance. The 9100 series needs the optional pendant to match the 4600 and 9200 series as they come.
The 9100 series needs the optional pendant.
The 9200 series comes with that functionality included.
The 4600 series comes with that functionality included, but the pendant's functions are moved to the 12v distribution circuit board. You can modify a 9100 style pendant to work with the 4600, but it is not necessary. I can see the need only if you can't bend down to see/operate the 12v distribution circuit board.