What you are asking for is possible only if the entire strategy based option is listed as a single product on the exchange.
In your example (I have taken 1 lot for simplicity)
Sold 40 Sep Put @ 27100 for Inr 160
Bought 40 Sep Put @ 27000 for Inr 120
Instead of 67k, assume only around 2.5k was charged (12k for 3.3, so around 2.5 for 67k).
What will happen if a client decides to exit the bought put option first? Should the platform allow a client to hold naked short option with just 2.5k in the account? - for whatever little time it takes to exit?
or, what if the client exits long put and then there is no liquidity on the short put position and he isn’t able to exit?
There are so many scenario’s where this can go horribly wrong and bring huge systemic risk to the industry. What you are asking for is possible only if the Short put spread was trading as a single product on the exchange. So a contract - Banknifty27100S27000B trading at Rs 40. Based on if you are bullish or bearish on the spread, you trade it directly.
Can the exchange introduce such contracts today and expect liquidity on it? I don’t think so, India is still atleast 20 years behind in terms of professionalism of the trading community compared to countries like US. The reason for this is we were introduced to derivatives only in 2000’s, whereas US has been using derivatives forever. Interest rate futures, VIX futures both fared miserably as a product when introduced here. VIX failing with so much option trading happening here was shocking.
https://zerodha.com/z-connect/queries/stock-and-fo-queries/trading-india-vix-simplified
So yeah, hopefully we will have option strategies listed as a product on the exchange over the coming years. But the first step towards that would be to make it more attractive for people trading strategies than trading naked positions by hopefully including Exposure as part of the SPAN margins itself.