The establishment works for 6days/week or < 6days/week?
The work hours are 8/day and 48/week. Then there is capping on OT hours.
If employee workd for > 48 hours /week OT is applicable.
Thed OT is calcultaed as; { ( Monthly wages/26)=per day wages}, { ( Per day wages/8)= per hour wages}
OT is @ double wages.
Accordingly you may calculate OT for 1 hour and check if it is =Rs.1000/
The company has termed OT as (ADJUSTEE) which is as per its internal language.
However each establishment has to submit registers ( might be allowed to submit self attested: Manually/digitla or electronic mode) prescribed under State Shops & Estbs Rules framed under State Shops & Estbs Act, and have to mention work hours and OT, in these.
It shall be Karnataka Shops & Estbs Act, Karnataka Shops & Estbs Rules in your case.
If you are unwilling to accept increase in notice period, you may decline to accept it, in writing either by letter or by email from your npersonal and official email id, and mention that increase is not beneficial to you OR you may diplomatically write that ' How the change is beneficial to you' and request to explain so that you can dwell on it.
Shops & Estbs Act is a state subject and Karnataka has granted exemption to IT/ITeS companies from standing orders.
Some acts of state of Karnataka and some clause of Karnataka Shops & Estbs Act are not employee friendly e.g;
Karnataka Shops & Estbs Act;
https://dpal.kar.nic.in/8%20of%201962%20(E).pdf
39. Notice of dismissal: (7) If under any other law or under the terms of an award, agreement or contract of service, any employee is entitled to a longer period of notice or to more favourable benefits that are provided in sub-section (1) or sub-section (3) the provisions of the said sub-sections shall have effect as if such period of notice and such benefits had been enacted in this Act.
There are many IT/ITeSemployees union in Karnataka and other states and have affilliated with Trade Unions and have done a good job also.
For the larger interest of employees the unions can take up such matters.
The above are suggestions only and you may consult elders of the family, well wishers, unions and able Labor Law Consultant before you act or write on your own.
Let your counsels draft your representations.