Supply of service with gta

A Service provide provide his service with Lorry Hire. His predominate service is C&F Charges. He will charge GST 18% including GTA Service. But the Service receiver says that GTA service is RCM. Hence do not charge the GST for the GTA Service. We will pay the GST under the RCM.

If the SP charge GST for GTA rate is 18%, if the SR pay GST under RCM GST is 5%.So the SR wants to pay GST for GTA under RCM. 

The question is that a Service provider can avoid charging GTA Service?