Is this correct?

I want to know when the difference in premiums of certain strike prices is an absolute number.
I already enabled it and i can see for myself the trigger should have alerted, but it didnt.
Can someone tell me if the code is right for sentinel?

LastTradedPrice(‘NFO:NIFTY2090311150CE’) - LastTradedPrice(‘NFO:NIFTY2090311200CE’) >= Math_Abs(15)