I am a newbie to writting FormCalc. I have tried to tweak your sample to fit my needs with no luck.
I have 6 fields for each weekday - in & out times for morning, afternoon, and overtime. I haven't even attempted to look at how overtime is calculated. Right now I am just trying to get the hours calculated for morning and afternoon minus the lunch break. I have attached a link to my feeble attempt in the hopes you could look at it.