Help with the Trix Signal Line

Hi Guys,

Can someone please give me a hand with the TRIX indicator.

To calculate the TRIX15 the formula is

 

1. Calculate the 15-day exponential moving average of the closing price.
2. Calculate the 15-day exponential moving average of the moving average calculated in step #1.
3. Calculate the 15-day exponential moving average of the moving average calculated in step #2. You now have triple exponentially smoothed the moving average of closing prices, greatly reducing volatility.
4. Finally, calculate the 1-day percent change of the moving average calculated in step #3.

If I am using 9 periods for the the TRIX signal line am I then calculating the 9 period MAs. I have done that on the ProRealTime platform that I am using but am getting slightly different results to there indiciator when using TRIX(15, 9)

Any help would be appreciated.

Regards
Steve