Report designer- Sum function doesn't add up properly

SUGGESTED

I'm trying to design my sale order template and I would like to add the Total Weight and the total packages into the sales order footer.

However, I tried the Add Expression, and I use the Sum Function, but it doesn't really do the job properly instead of doing 1+2 it is doing 1+(1+2).

Below is the formula that I used

Total Weight

sum(SOP_ITEM.QTY_ORDER * STOCK.UNIT_WEIGHT)

Total number of Packages

sum(SOP_ITEM.QTY_ORDER)

Please help