it has to be something else, I have that set as well?
I just tried on my site. The ws_bloomsky file is located in _my_scripts folder, not sure if that matters along with the bundled files.
When I use these setting its switches to metric units:
#$bl_intl_units = true; // for non-us display of data
$bl_intl_units = true; // remove # when using imperial unitsWhen I use these setting is switches back to US units
#$bl_intl_units = true; // for non-us display of data
$bl_intl_units = false; // remove # when using imperial units