ASKWB

Advance Medical Leave
For additional posts, no leave other than casual leave is admissible.

But i have heard that we can get 365 medical leave in our whole service life.

A teacher or a non-teaching employee of a school may be granted 15 days’ leave on medical ground for each completed year of service spent on duty. The total period of leave on medical ground, which may accrue to the credit of a teacher or a non-teaching employee shall not exceed one year, that is, 365 days during the whole period of service. During the period of leave on medical ground the teacher or the non-teaching employee will get a salary at the rate of full average pay.

Then, the said 40 leave may not be adjusted with medical leave?

As per Board’s No. Kol-2327/04/G dated 11.04.2004, any teacher absenting himself or herself from the school on medical ground in his/her first year of service, can be granted medical leave with/without pay by the Managing Committee and the said leave shall be adjusted to the medical leave which will be acrued to his/her credit in subsequent period of his/her service.
I think that you may avail Medical leave with pay for 15 days and without pay for rest 4 days for the first year of Service. As there is no clear cut instruction for the second year of service for the Additional post, I think the matter may be referred to the Higher authorities.
Lets see what our other friends say. you may have a look at the following links for more info.
1. Additional Post Vs Normal (Permanent) Post
2. Study Leave for Additional Posts
3. Leave Rule of Secondary School Teaching / Non Teaching Staff