Is it valid to deduct BOCW cess without civil work? Is BOCW cess calculated on the gross amount of invoice (including GST)?

Dear All, Please guide that, Our Organization working on project of HPCL (Mechanical Work) but there are Civil work included in Mechanical work order, SOR mentioned step by step work for Scope of work for Civil too.
CIVIL Site still not hardcovered so we started Mechanical works and raised invoice for same mechanical work,
Now they are calculation BOCW Cess on the whole amount of invoice including GST (while the invoice not belong to Civil works)
please guide and kindly refer any law related to this
Is it valid to deduct BOCW cess without civil work while they still have not handover the civil site?
Is BOCW cess calculated on the gross amount of invoice (including GST)

The GST is to be paid at fixed rate on Cess which is calculated @1% of the cost of construction invoiced to the employer. This cost of construction, may be for Mechanical, Civil and Electrical work done by the contractor.
The contractor has to pay for the cost of cess @1% on work order value as per which the registration obtained. You ask the employer to issue the work order for the civil work, if the work not included in work order.

Pl see the definition of Construction work.

As per Section 2(d) of the BOCW Act, "building or other construction work" includes "the construction, alteration, repairs, maintenance or demolition- of or, in relation to, buildings, streets, roads, railways, tramways, airfields, irrigation, drainage, embankment and navigation works, flood control works (including channels for distribution of water), oil and gas installations, electric lines, wireless, radio; television, telephone, telegraph and overseas communication dams, canals, reservoirs, watercourses, tunnels, bridges, viaducts, aquaducts, pipelines, towers, cooling towers, transmission towers and such other work as may be specified in this behalf by the appropriate Government, by notification but does not include any building or other construction work to which the provisions of the Factories Act, 1948 (63 of 1948), or the Mines Act, 1952 (35 of 1952), apply;

See the nature of your work and evaluate whether the specific items mentioned above fits your activity.

Dear Sir,
Thanks for information
i have another query , is BOCW Cess will be calculated on amount of invoice generated with GST or Base amount (without GST).