Not sure what is going on here but when you try to sum numbers that end in .9 it does weird things.
I tried .1 through .8 and it works just fine. Just .9 is off
All 3 and Decimal type with a formula of
${Loc1FloodWidth1} + ${Loc1FloodWidth2} + ${Loc1FloodWidth3}
On testing it seems that if you have 2 numbers and one is .Even and one is .Odd.
Thanks