GST on hiring of motor vehicle

Are you Goods Transport Agency or the Service Receiver ?

Then how are you concerned with the issue ?

Yes if you opt for 5% , the G.TA cannot avail I.T.C on their inputs, where  as in case of 12% , they can avail input on their input services.

If it is the case of service which is liable for reverse charge, the G.T.A  need not care of the tax and it is the recipient has to pay on reverse charge basis. 

In general, where there is no explicit provision to this effect , you may prompted to pay the differential tax between 12 and 5.