Advance received by composition dealer

Discharging GST at one rate at the time of advance receipt and different rate applicable at the provision of service. Typical example could be at the time receipt of advance, hotel might have paid GST @ 18% but the room provided having a tariff between Rs. 1,000/- to Rs. 7,500/- where the rate of GST is 12%.

Yes service provider needs to discharge gst liability on advance received

The concept says
that gst is payable if the following conditions are satisfied:
1. the intention of the individual dealing in goods or services.
2. for furtherance of business
3. the taxable person intends to receive advance for furtherance of business.
4. must raise invoice
5. but after full work has been completed.
He can raise gst.