Hi,
to fix this problem. Open this Language file:
/administrator/language/en-GB/en-GB.plg_flexibleTemplate.ini
find this line:
TPL_FLEXIBLE_GROUND_TOTAL="Ground Total:"
and change it to this:
TPL_FLEXIBLE_GROUND_TOTAL="Grand Total:"
you will be good to go.
FYI: I am making this patch permanent in the CleanMart right now.