Thanks for your time bebo021999
Yes we have a communication gap
Let me explain it this way.
The prisoner was undertrial from 12th Feb 2016 to 11th May 2016 then he was out on bail.
The court gave him the setoff period for his undertrial days when he got convicted for 4 years on 04-05-2018
So we calculate it this way, we put his release date manually as 03-05-2022 i.e 4 years.
Than from 03-05-2022 we minus his undertrial period i.e 2 months and 29 days so we get his release date as 03-02-2022.
From 03-02-2022 we start to minus his sentence served in prison starting with the first month that is without remission as he was convicted on 04-05-2018 he won’t be eligible for remission as the criteria for remission is for complete month.
So when we minus the sentence served in jail for the month for May 2018 we minus 28 days as he was convicted on 04-05-2018 and we minus it from 03-02-2022 so the calculation so far is

Actual date of release 03-05-2022 – 2*30-29 = 02-02-2022
We minus the 2 Months manually that comes to 03-03-2022 and the month of Feb in 2022 is of 28 days so after deduction the 29 days manually it comes to 02-02-2022

Now we minus his remission of 298 days
The remission break up of 298 days is as follows
Year 2018 from June to Dec i.e 7 months so 7months *7 = 49
Year 2019 From Jan to Dec i.e 12*7 = 84 Plus 30 days as he completes the calendar year so the additional 30 days for 2019
Year 2020 From Jan to Dec i.e 12*7 = 84 Plus 30 days as he completes the calendar year so the additional 30 days for 2020
Year 2021 From Jan to Mar i.e 3*7 = 21 as he is released in the month of April he won’t get the remission for April as the month is not getting completed
SO the total remission is 49+114+114+21 = 298
so we minus 9 months i.e 270 days and the remaining 28 days from the date we got after deducting his under trial day. That is to minus 9 months from 02-02-2022 so we get the date as 02-05-2022.
Now we deduct 28 days from the 02-05-2021 we get the date as 04th April 2021.
4th April been a Sunday he is released a day earlier on 3rd April