You can use subcontracting rates for subcontracting with material flow as well as for subcontracting without material flow:
Subcontracting with material flow
If you use subcontracting with material supply, and the Source of Price field in the Items - Purchase (tdipu0101m000) session is Subcontracting Rate, LN uses
the subcontracting rates to calculate subcontracting costs
Subcontracting without material flow
If you use subcontracting without material flow, you must
use this session to enter subcontracting rates so that LN can calculate
subcontracting costs. You must enter an item of the Subcontracted Service type in the Subassembly field. This item represents the
subcontracted operations, and is displayed on the subcontracting purchase
order.