Hello & welcome lilewis !
the camera shows 1/3,200 @ f2.7
That's the normal behaviour with CHDK: The Canon firmware don't know anything about the CHDK override settings...
The Canon-OSD of the camera always show the min. /max. available Canon-setting, the adjusted CHDK settings are shown only in the CHDK OSD in "Miscellaneous Values" which can be enabled/disabled in the CHDK menu ("Show Set Exposure Ev" in the "Miscellaneous Values" menu, disabled by default):
-> set "Show misc values" to "on half shoot" & check the values you want to see...
That's also the reason why the EXIF data of the CHDK-enhanced images doesn't contain the "real" override values...the high speed shutter overrides are working, check the resulting pictures...
The maximal possible settings are highly dependent from the camera model & the electrical / mechanical data, you can find some more informations in the CHDK wikia in
Camera Features...
...and remember: for high speed shutter records you'll need 'tons of light' - use the flash !
*Edit: typos...