This is much better:

DEFPARAM CalculateOnLastBars = 1000
//MaxOC     = max(open,close)
//MinOC     = min(open,close)
//MyH1high  = highest[4](high)
//MyH1low   = lowest[4](low)
//MyH1MaxOC = highest[4](MaxOC)
//MyH1MinOC = lowest[4](MinOC)
//MyH1Open  = max(MyH1MaxOC,MyH1MinOC)
//MyH1Close = min(MyH1MaxOC,MyH1MinOC)
//IF hour <> hour[1] THEN
//DRAWCANDLE(MyH1open,MyH1high,MyH1low,MyH1close) coloured(0,128,0,16) BORDERCOLOR(0,128,0,128)
//ENDIF
H1high  = highest[4](high)
H1low   = lowest[4](low)
H1Open  = open[3]
H1close = close
IF hour <> hour[1] THEN
   DRAWCANDLE(H1open,H1high,H1low,H1close) coloured(0,0,0,255) BORDERCOLOR(0,128,0,128)
ENDIF
RETURN

You will define HA candles for the 15-minute TF as usual, while for the 1-h TF you’ll need to write:

IF hour <> hour[1] THEN
   xH1Close  = (H1open+H1close+H1low+H1high)/4    //TotalPrice
   xH1Open   = (xH1Open[1]+xH1Close[1])/2
   haH1High  = Max(xH1Open, xH1Close)
   haH1Low   = Min(xH1Open, xH1Close)
   xH1High   = Max(H1High,haH1High)
   xH1Low    = Min(H1Low,haH1Low)
else
   xH1Close  = xH1Close[1]
   xH1Open   = xH1Open[1]
   xH1High   = xH1High[1]
   xH1Low    = xH1Low[1]
endif

x-5.jpg