X(USA) has signed contract with Y(India) for production of goods & export to X.Mould was to be provided by X as per contract. X has given advance of ₹ 50 L to Y for purchase of mould in India & to be retained by Y for production. Y purchased mould from Z(India) & availed GST input on this. Should Y raise export invoice of mould to X(though physically to be retained by Y)? or Y shall add amortised cost of mould in export invoices of goods to X? is input eligible on purchase of mould by Y from z.