Difference in strike in instrument name and position builder

I have created a strategy where EMA of ATM-2 strikes are being compared for entry. This “ATM-2” strike in entry set is achieved through Instrument Name keyword. There is no issue in this.

But the same strike is required in position builder also. So, in the Strike–> selected Fx—> Now, Round formula with Instrument as Nifty Spot. Now, this provides, not ATM strike, always.

Ex: If spot is 17122, then as per NSE, ATM should be 17100. But Round formula is rounding it to 17150. So, the trades are taken as 17150, not as 17100.

But if Nifty spot is 17140, then ATM should be 17150 and then the formula works.

This is as per my experience. Please suggest how to correct this.

Use round to 50 for ATM