Checking for a new row entry on Subform onSuccess or on User Input on edit.

Checking for a new row entry on Subform onSuccess or on User Input on edit.

Hey there,
How can I check if a new subform row is been added on edit workflow while on success or on user input as I am calculating subtotal from the subform to main form field total.?

Any help would be appeciated.

Thanks in advance!