GST ...12% or 18% on real estate

i have booked a flat in Ernakulam in 2014 which is still under construction. so far I have been paying 11% tax. As per the new GST which will be implemented from july 1, what will be the GST applicable in my case.. Will it be 12% or 18% . As per the SCHEDULE OF GST RATES FOR SERVICES AS APPROVED BY GST COUNCIL , under 19 Clause : Construction of a complex, building, civil structure or a part thereof, intended for sale to a buyer, wholly or partly. [The value of land is included in the amount charged from the service recipient] is 12% With Full ITC but no refund of overflow of ITC. However, under Clause 27, it read as, Composite supply of Works contract as defined in clause 119 of section 2 of CGST Act is 18% With Full ITC. Please clarify the difference, and also let me know which will be applicable for me.12 or 18..Flat will be ready for possession in January 2018.