Winhex Templates

Im trying to write a new template in Winhex but having trouble with the Uint_Flex variable so wondering if anyone has done some work with templates and knows a way around it.

I've got a variable and wish to use it for a loop and if statement but I get errors saying Invalid integer number.

uint_flex "2,1,0" "Offset1"
numbering 0
{
byte "B[~]"
} [(3^Offset1)]

And further down I wish to do an if comparision with the same variable but get the same probelem saying invalid integer. Is there anyway to turn these bits I've extracted using uint_flex into a valid integer that can be used in loops and if statements etc?

Thanks for any help.