Moving Average Method indicator

"Average-Modified Methodius indicator
From The New Commodity Trading Systems and Methods by Perry J.. Kaufman
Chapter 4 - Moving Averages, pg. 60th
This formula is for version 6.5 on MetaStock for Windows 95 and NT only and can not be written in the previous version.
This modified simple moving average.
The formula will prompt you to enter the number of periods to use moving averages.
Day: = Cum (1) 1;
Z: = Input ("period", 2,1000,5);
MV: = (1 / h);
If (Day <(Z +2), C, If (day = (Z +2), MOV (C, LastValue (W), S), previous + (MV * (C-last))))