YES, you are right. There is a slight difference in value. I generally use p=200. It was recommended for indices.
But the “P” values, as traders recommend, should be multiple of eight because the indicator is based on eight lines. Traders often use 16, 64, 128, 256. 16 is considered to be used very rarely, probably due to a very short period for building lines on a price chart.
Robo forex is using 256 most probably. Now it is up to you... Better we should go with p=256!