If you can reorganise your tables then try this:
tblStyle
StyleID - auto
style
color
size
1. tblForecast
fields: styleid,week,units
2. tblWIP
fields: styleid,week,units
3. tblOnOrder
fields: styleid,week,units
4. tblOnHand
fields: styleid,week,units
Then these tables can be linked together on...