Also the ESIC calculation will be based upon the Gross and not on any specific amount. Similarly OT also have to be provided as per the calculation laid down under the Labour Laws. Please try to understand that Rs 5,000/- for OT may be may be less or more than the actual calculated amount. If the calculation of OT is more than Rs 5000/-, it will be not only deemed as non compliance but also as exploitation!
If you pay this specific OT at every month, you will have to pay ESIC and even PF.
7th June 2018 From India, Kolkata