iMA 함수에 관한 질문입니다.

MetaEditor 에는 iMA 함수가 아래와 같이 설명되었습니다.

double iMA( string symbol, int timeframe, int period, int ma_shift, int ma_method, int applied_price, int shift)

symbol   -   Symbol the data of which should be used to calculate indicator. NULL means the current symbol.
timeframe   -   Timeframe. It can be any of Timeframe enumeration values. 0 means the current chart timeframe.
period   -   Averaging period for calculation.
ma_shift   -   MA shift. Indicators line offset relate to the chart by timeframe.
ma_method   -   MA method. It can be any of the Moving Average method enumeration value.
applied_price   -   Applied price. It can be any of Applied price enumeration values.
shift   -   Index of the value taken from the indicator buffer (shift relative to the current bar the given amount of periods ago).
 

AlligatorJawsBuffer[i]=iMA(NULL,0,13,8,MODE_SMMA,PRICE_MEDIAN,i);

ma_shift의 값 셋팅법과 샘플에서 8로 셋팅하는 의미 조차 잘 모르겠습니다. ㅜㅜ