I look at it this way…Langmuir designed a box that takes the actual voltage readings and converts it to the proper input for their machines to run with…just like they designed the table to work really well with the plasma cutter they sell with their tables…
Even though the books and people can say you can just remove a jumper…or solder in wires in places to get the divided voltage…it is not the true voltage as it goes through circuits to get to the pins…
If you ever have to trouble shoot a problem…you measure right off the box equipment Langmuir sold and supports…not have to guess where inside the plasma you need to go…or if there is a problem with your plasma…saved me a lot of time at the start.