Parameterized PCell Schematic

I'm running into some problems creating a PCell schematic.

The PCell I'm creating is attempting to wrap an nmos pcell so that I can parameterize it's W,L, and M

Here is a snippet of my code:

pcDefinePCell(
list( ddGetObj("ASTparameterized") "nmoslgi_a" "schematic" "schematic")
(
(width "string" "1")
(length "string" "1")
(mult "string" "1")
)
let( (cv)
cv = pcCellView
fprintf(stdout "RUN\n")
dbD_0x1545979a = dbOpenCellViewByType("au1Comp" "nmoslgi_a" "symbol")
dbD_0x22fe0b1a = dbCreateParamInst(cv dbD_0x1545979a "MN0"
1.437500e+00:1.875000e-01 "R0" 0
list(
list("M" "string" mult)
list("W" "float" cdfParseFloatString(width))
list("L" "float" cdfParseFloatString(length))
)

CCSinvokeCdfCallbacks(pcCellView ?callInitProc t ?useInstCDF t)

)

When I try to pass using [@NM] or pPar("NM") neither seems to work properly. It does at least show the right W/L/M values when I just pass values.

The whole reason I am doing this is because the nmos pcell has a callback that is executed every time the W/L is changed.