A Pvt. Ltd., a registered manufacturer, sent steel cabinets worth Rs. 40 lakhs under a delivery challan to B Ltd., a registered job worker, for job work on 02.01.20XX. The scope of job work included mounting the steel cabinets on a metal frame and sending the mounted panels back to A Pvt. Ltd. The metal frame is to be supplied by B Ltd. B Ltd. has agreed to a consideration of Rs. 4 lakhs for the entire mounting activity including the supply of metal frame. During the course of mounting activity, metal waste is generated which is sold by B Ltd. for Rs. 55,000. B Ltd. sent the steel cabinets mounted on the metal frame to A Pvt. Ltd. on 03.12.20XX.
Assuming GST rate for metal frame as 28%, for metal waste as 12% and standard rate for services as 18%, you are required to compute the GST liability of B Ltd. Also, give reason(s) for inclusion or exclusion of the value of cabinets in the job charges for the purpose of payment of GST by B Ltd.