Interim maintenance calculation for wife with qualification

Hello, I wish to put forth my case for your valuable guidance and advise. I earn a salary of 1,25,000. I have received a notice from my wife under the section of 13 ia on cruelty grounds for divorce and she has demanded an interim maintenance of 50,000 rupees. I had purchased a flat in the joint name of me and my wife. I have made the complete down payment for the same and paying 51,549 as the monthly emi payment. The rental income from the flat is 14,000. I have my mother to be looked after. My wife has taken my 2 year old daughter along with her. It's been 3 years to the marriage and she deserted me 6 months back. As I read through the blogs here, I get to understand that the interim maintenance is 1/3 of the net monthly income. In my case, I calculate it as 1,25,000 + 14,000 rent i.e. 1,39,000. The expenses are emi of 51,549. Domestic grocery expenses of 6,000 and medical fees for mother of 3,000. Expenses roughly 60,000 along with emi. The net income is around 80,000. I am expecting an interim maintenance value of roughly 25,000. Wanted to know whether I can reduce it further by any means. I am fully aware that this amount shall result in future steps taken by the wife. I am already paying the emi completely. The loan amount is 45 lakhs. There is no percentage share in property mentioned. Hence it shall be decided as 50_50. Please advise as to how I can take steps to reduce the interim maintenance and in case wife agrees for mutual divorce, which I don't want as I very much want to continue my marriage.; What would be the meaningful lumpsum amount which can be thought of. She is qualified but currently unemployed as stated by her. She is a free lancer and takes online Skype musical classes and teaches offline, does music program too.