GST TDS u/s 51

Mr. A provide repair & maintenance service of transformer to Mr. B under a contract ( value Rs 20,00,000)
During the repairing some scrap material arise which given to Mr. B for consideration of Rs 5,00,000/-

The invoice has been issued in following manner :
Amount for rendering
of service Rs 20,00,0000
Less:
Material provide Rs 5,00,000

Balance Rs 15,00,000
Add : GST @ 18%. Rs 2, 70, 000
Total. Rs 17,70,000
Less:
GST TDS @ 2%. Rs 30,000
GST on scrap. Rs 90,000

@ 18% on Rs 5,00,000
on rs 15,00,000/-

Net Amount paid to
Mr. B.(17,70,000-30,000,90,0000)
= 16,50,000/-
the above treatment is correct as per GST provision.