Me suma MAL los decimales!

[ElPadrino]

Error "13" en linea de tiempo

no coinciden los tipos

este es el codigo

dim iva1 as double
dim iva2 as double
dim iva3 as double
dim iva4 as double
dim iva5 as double
dim iva6 as double
dim iva7 as double
dim iva8 as double
dim iva9 as double
dim iva10 as double
dim iva11 as double
dim iva12 as double
dim iva13 as double
dim iva14 as double

dim subt1 as double
dim subt2 as double
dim subt3 as double
dim subt4 as double
dim subt5 as double
dim subt6 as double
dim subt7 as double
dim subt8 as double
dim subt9 as double
dim subt10 as double
dim subt11 as double
dim subt12 as double
dim subt13 as double
dim subt14 as double

dim subtotal as double
dim impuestos as double
dim total as double

iva1 = cdbl(text17.text)
iva2 = cdbl(text26.text)
iva3 = cdbl(text35.text)
iva4 = cdbl(text44.text)
iva5 = cdbl(text53.text)
iva6 = cdbl(text62.text)
iva7 = cdbl(text71.text)
iva8 = cdbl(text80.text)
iva9 = cdbl(text89.text)
iva10 = cdbl(text98.text)
iva11 = cdbl(text107.text)
iva12 = cdbl(text116.text)
iva13 = cdbl(text125.text)
iva14 = cdbl(text134.text)

subt1 = cdbl(text18.text)
subt2 = cdbl(text27.text)
subt3 = cdbl(text36.text)
subt4 = cdbl(text45.text)
subt5 = cdbl(text54.text)
subt6 = cdbl(text63.text)
subt7 = cdbl(text72.text)
subt8 = cdbl(text81.text)
subt9 = cdbl(text90.text)
subt10 = cdbl(text99.text)
subt11 = cdbl(text108.text)
subt12 = cdbl(text117.text)
subt13 = cdbl(text126.text)
subt14 = cdbl(text135.text)

subtotal = cdbl(text145.text)
impuestos = cdbl(text146.text)
total = cdbl(text147.text)

text145.text = iva1 + iva2 + iva3 + iva4 + iva5 + iva6 + iva7 + iva8 + iva9 + iva10 + iva11 + iva12 + iva13 + iva14

text146.text = subt1 + subt2 + subt3 + subt4 + subt5 + subt6 + subt7 + subt8 + subt9 + subt10 + subt11 + subt12 + subt13 + subt14

text147.text = subtotal + impuestos