You can set a default setting for this, so you don't have to manually change it to 'total mg' or 'total ml' each time you add a new medication.
To change to the desired default, go to "Settings" > "General" > "Medication Units". Toggle the switch to your preferred choice:
You can also customize the display units of any medication in Smart Flow from the 'Edit' screen of that medication. This works on both the Flowsheets and the Anesthetic Sheets.