How can I prevent /etc/default/keyboard from overriding my xorg xkb configurations?

How can I prevent /etc/default/keyboard from overriding my xorg xkb
configurations?

I have the following file at /etc/X11/xorg.conf.d/11-TECK-keymap.conf
Section "InputClass"
Identifier "TECK"
Driver "evdev"
# If you save this file under xorg.conf.d/ :
Option "AutoServerLayout" "on"
MatchIsKeyboard "on"
MatchProduct "TrulyErgonomic.com Truly Ergonomic Computer Keyboard"
### at-home-modifier options begin here.
# The basic option.
Option "XkbLayout" "us"
Option "XkbVariant" "altgr-intl"
Option "XKbOptions" "lv3:ralt_switch_multikey,numpad:pc,ctrl:swapcaps"
Option "TransMod" "36:64"
EndSection
I know that MatchProduct is correct, as Option "TransMod" (the
at-home-modifier option) works on this specific keyboard. However, the Xkb
lines don't work, unless I comment out the MatchProduct line.
I've found that (with MatchProduct present) the Xkb lines are being
overwritten by /etc/default/keyboard. I've tried deleting this file, and
commenting it out, but I still cannot get the xorg xkb options to stick.
(P.S. I'm using KDE, but "Configure layouts" and "Configure keyboard
options" are unchecked in System Settings.)