Section 15(2) (b) of CGST Act

Section 15(2) (b) of CGST act read as follows
any amount that the supplier is liable to pay in relation to such supply but which has been incurred by the recipient of the supply and not included in the price actually paid or payable for the goods or services or both;
my question is that only liabilities of supplier relating to such supply is added to value of supply or the overall liabilities of supplier is added (eg bank loan etc)