為何改變布林軌道上緣參數，卻還是沒變?

Input: Length(28, "BBand軌道線長度"), UpperBand(3, "上通道標準差");
variables: UpperBandPos(0);

settotalbar(Length + 4);

UpperBandPos = bollingerband(close, Length, UpperBand);

if close[1] cross Under UpperBandPos  and (h-l)/2+l<= UpperBandPos then begin
    plot1(UpperBand,"UpperBand");
end;