Arranging task bar with multiple monitors (works but why)

[Dexter Filmore]

Hi all,

I suspend this xfce machine usually, and when waking the machine the monitors 
come up in different orders, so I wrote me a little script that places 
monitors where they physically are and taskbars where they belong.

Question: why did this not work, leaving the second bar untouched:

#!/bin/sh
xrandr --output HDMI-1 --mode 1920x1200 --pos 0x0 --rotate normal --output \ 
HDMI-2 --mode 1920x1200 --pos -1920x0 --rotate normal --output \ 
HDMI-3 --off --output DP-1 --off
xfconf-query -c xfce4-panel -p /panels/panel-1/output-name -s HDMI-2

...while this one works, first telling the system to place panel 1 on hdmi-1, 
then on -2.

#!/bin/sh
xrandr --output HDMI-1 --mode 1920x1200 --pos 0x0 --rotate normal --output \ 
HDMI-2 --mode 1920x1200 --pos -1920x0 --rotate normal --output \ 
HDMI-3 --off --output DP-1 --off
xfconf-query -c xfce4-panel -p /panels/panel-1/output-name -s HDMI-1
xfconf-query -c xfce4-panel -p /panels/panel-1/output-name -s HDMI-2

Curious,

Dex