Why doesn't converted script calculate the same as original when converting from V2 to V4 in Pinescript

When converting a script from V2 to V4 in Pinescript, it doesn't appear to be calculating the same.

V2:

study(title = "POC bands 2.0", shorttitle="POCB", overlay=true)
resCustom = input(title="Timeframe", type=resolution, defval="240")
Length = input(6, minval=1)
xPrice = security(tickerid, resCustom, hlc3)
xvnoise = abs(xPrice - xPrice[1])
nfastend = 0.666
nslowend = 0.0645
nsignal = abs(xPrice - xPrice[Length])
nnoise = sum(xvnoise, Length)
nefratio = iff(nnoise != 0, nsignal / nnoise, 0)
nsmooth = pow(nefratio * (nfastend - nslowend) + nslowend, 2) 
nAMA = nz(nAMA[1]) + nsmooth * (xPrice - nz(nAMA[1]))
basis = nAMA
atr = ema(tr,11)
upper = basis[3] + (atr*3)
lower = basis[3] - (atr*3)

plot(basis, color=blue)
plot(upper, color=blue)
plot(lower, color=blue)

V4:

study(title = "POC bands 2.0", shorttitle="POCB", overlay=true)
resCustom = input(title="Timeframe", type=input.resolution, defval="240")
Length = input(6, minval=1)
xPrice = security(syminfo.tickerid, resCustom, hlc3)
xvnoise = abs(xPrice - xPrice[1])
nAMA = 0.0
nfastend = 0.666
nslowend = 0.0645
nsignal = abs(xPrice - xPrice[Length])
nnoise = sum(xvnoise, Length)
nefratio = iff(nnoise != 0, nsignal / nnoise, 0)
nsmooth = pow(nefratio * (nfastend - nslowend) + nslowend, 2) 

nAMA := nz(nAMA[1]) + nsmooth * (xPrice - nz(nAMA[1]))
basis = nAMA
atr = ema(tr,11)
upper = basis[3] + (atr*3)
lower = basis[3] - (atr*3)

plot(basis, color=color.new(color.blue,0))
plot(upper, color=color.new(color.white,0))
plot(lower, color=color.new(color.white,0))

V2 are the blue bands with a red center and V4 are the white bands with a blue center.