ESIC duration months - as per HR my Gross increased more than 21000

I am working with Pvt concern and after appraisal my salary increase from 18580 to 20798. April`18 My salary after deduction comes out to be 20798 RS , as per HR my Gross increased more than 21000. Now i am going to confirm till when my ESIC amount deducted from my salary or it is already close form month of April`18.

Hi Vijay,
Closing option gets enabled in the month of April and October. Your contribution would have ended if your gross salary per month exceeds 21000

Dear Vijay ji,
What I understood that in the month of April 2018 your salary is increased & you earned Net Rs. 20798.
Net earning is not your salary. Gross amount is your salary. Your gross seems to be more than Rs. 21000.
If it is so that in the month of April 2018 your gross is more than Rs. 21000 then from April 2018 onwards you should be out of ESI.
In the month of April & October, if gross is above Rs. 21000 then the employee de-coveres from ESI.