Taxable value & Rate of GST

I have booked a hotel room @2000/- + 12% GST i.e. Rs.2240/- through an agent who has agreed to charge @5% commission on room tariff. How will be the break up of tax invoice raised by the agent to me?

Room tariff = 2000/-

commission @5% = 100/-

Total Taxable Velue = 2100/-

GST @18% on total taxable value = 378/-

Gross Amount = 2478/-

OR

Room tariff = 2000/-

commission @5% = 100/-

Total Taxable Velue = 2100/-

GST @18% on commission = 18/-

Gross Amount = 2118/-

OR

Hotel cost = 2240/-

commission @5% = 100/-

Total Taxable Velue = 2340/-

GST @18% on commission = 18/-

Gross Amount = 2358/-