Hi Kishore,
Subtotal value can be captured either from a Condition type or through a Value line in a Pricing procedure.
The value of a Subtotal will be available in structure and can be used for further calculations some other purpose.
For example, Subtotal A is holding a value, which is used to cumulate the value and used for credit management.
Similarly we can define our own Subtotal and can use it for our intended purpose.
Regards,
Raja Durai