Nifty options trading

Calculations based on data on 11/12/2019

Nifty spot 11860 expiry Dec 26

Based on assumptions that Nifty will have an expiry in the range of 11970 - 12100.

Buying 1 lot Nifty 11900 CE @ 138 & selling 2 lot Nifty 12000 CE @ 89 per lot (89 x 2 = 178)
total credit (178 - 138) = 40/-

This strategy might gain highest profit if nifty expiry is near to/ or 12000
unlimited loss will start above 12140
if nifty expiry is 11900 or below, strategy will still gain 40/- per lot of strategy.

Can someone analyse the above and let me know the loopholes of this strategy in detail?
what other expenses should be taken care of while calculating profits of such strategy?
Is is ok to adopt such trade? what are other possibilities of loss in such trade?

can you plz explain.

Kindly explain:
1- where can I perform the study you have shared?
2- What is the significance of 11958?
3- What is total PNL -802.5 ?

https://opstra.definedge.com/strategy-builder