EPCM Allocation rule allocates many zero values

Summary:

We need to allocate each business expenses using sales as a driver.

We have some new business, with no sales. In those cases, we need to allocate its expenses evenly.

We built 2 allocation rules

1) First rule allocates expenses using sales as a driver. It allocates expenses from business with sales (balance=0 in these business), and leaves expenses from business without sales (balance <> 0 in these business)

2) We built a second rule, which allocates expenses evenly. It works for business without sales, but it also allocates 0 to business with sales. 

It takes time and updates many cells unnecesary, writing 0 as a result.