I was wrong, I meant the change in the Range Surge Indicator !

Is this what you mean by the range surge indicator?

100 * (H - L) / AVG(H - L, 21)

If it is, it just divides the range of the current bar by the 21 period simple moving average of range. The only real parameter would be the 21, which is the period of the moving average.

The change in this formula from the previous bar to the current bar can be written as follows.

100 * ((H - L) / AVG(H - L, 21) - (H1 - L1) / AVG(H1 - L1, 21)) 

So, wanting to restrict to anticipate the signal would be enough to change the period 21 - 13 - 8 ?

I am not sure what, "wanting to restrict to anticipate the signal" means, but you can definitely change the 21 to 13 or 8 instead.

Well what would be the signal? You haven't indicated what the signal might be. Greater than 100? If so, you could write it as either:

100 * (H - L) / AVG(H - L, 21) > 100

Or as:

H - L > AVG(H - L, 21)

You're welcome.