DDM (U2414H) - Targeting display by serial number with command line?

I have two U2414H displays which I use both with my gaming desktop and my work laptop. The system I have set up goes like this:

• USB-C laptop dock with HDMI-outs going to my monitors' HDMI2 inputs
• Desktop GPU with HDMI-out and DP-out going to my monitors' HDMI1 and Mini-DisplayPort inputs
• Mouse and keyboard plugged into a USB 3.0 KVM switch, with one source going to the desktop and the other source going to my laptop dock

Currently to switch systems, I have to hit the button on the KVM switch to switch over my peripherals, and then go through the monitors' OSD menus to switch the input sources. The extra step with the monitors is necessary because I want to leverage my GPU with my gaming desktop instead of going through the DisplayLink USB graphics.

To simplify the process of switching display inputs, I'd like to just make a .bat file on each system that will use the Dell Desktop Manager CLI to switch my monitor inputs over to the other source with one click. The readme.txt says that you can target a display by serial number, but that doesn't seem to be working for me. I've tried the full serial number with and without dashes (i.e., ddm.exe /CN-0FN8GP-74261-68S-1M5L-A03:SetActiveInput mDP and ddm.exe /CN0FN8GP7426168S1M5LA03:SetActiveInput mDP), but neither of those commands seem to be doing the trick. Using /1 or /2 does work, except that which display receives which command doesn't seem to always be consistent.

TL;DR: How do I target a display by serial number with Dell Desktop Manager's CLI? I've tried the full serial number with and without dashes and neither format seems to be working.

For reference, here's the relevant line in the readme:

Command language
-----------------------------------------------
A rich and flexible command language is supported via the
command-line, and command-line arguments can be combined.
Where appropriate, a specific display can be targeted by
prefacing the command with the monitor serial number or
enumerated display number, e.g., "2:AutoSetup"; if a
display serial or enumerated number is not specified the
command will be applied to the current selected display
or to all displays, as appropriate.