Please, some help with a formula

[Jim & Lana <plaid@xxxxxxxxxxxx>]

I have found an indicator that Linda Rashke uses.  It is based on a
Keltner Band, "I put Keltner channels set at 2.5 times the 20-day moving
average daily range, centered around the 20-period moving average."

I have been struggling with this, I assume, simple formula, and find I
am doing something wrong, the bands are to wide or look so very narrow.
Keltner Bands use a 10 day moving average so I have substituted "20" for
the "10".  Here is a Keltner Band formula from Equis, could someone
please help me get a 2.5 standard deviation on this thing.  I would
really appreciate it....Lana..

Formula #1:

Name :20 Day Moving Average
Formula:  MOV((H+L+C)/3,20,Simple)

Formula #2:
Name:  Upper Keltner Band
Formula: MOV((H+L+C)/3,20,S)+MOV((H+L),20,S)

Formula #3:
Name:  Lower Keltner Band
Formula:  MOV((H+L+C)/3,20,S)-MOV((H-L),20,S)