Dear Mr. Pereira,
I have read information furnished by you regarding treating of 40% wages out of total bills as above for ESI compliance. However, for discussion sake I may inform your goodself that in support of your above information there may be old instructions issued by the ESIC authorities. But in actual practice, the same are not followed, resulting into claim on treating 100% amount of bill as wages for claiming of ESI contribution on such omitted wages.
In my opinion, the safe practice is that as an when the employer appoints any person as contractor or casual labour for such job work, then employer should insist for maintenance of Attendance & Wages Registers of such contract/casual employees and pay ESI contribution on actual wages.Payment of such ESI contribution on actual basis and making of compliance on actual basis in respect of such contractor/casual employees will also entitle such employees for various benefits under Employees' State Insurance Act, 1948 and rules/regulations framed thereunder.
Further, I think,the acceptance of 40% as wages out of a bill of job work as mentioned by you is also not within the jurisdiction of appropriate Social Security Officer of your area.
If you have any doubt, I think, you can confirm the position from appropriate Regional/Sub-Regional Office of ESIC.
With regards;