Term for calculated values that lose pertinence when changing scale
Let us think of sales ($S$) as a property of a system.  You could imagine Week 1 to be a system and Week 2 to be another system.  Call the Week 1 system $W_1$ and the Week 2 system $W_2$.  Then,
$$
  S(W_1) + S(W_2) = S(W_1 + W_2)
$$
A property that has this additive character is called extensive.  

Now consider the temperature ($T$) as the property with values $T(W_1)$ and $T(W_2)$ for weeks 1 and 2.  Assume that the two $T$ values are identical.  Merge the Week 1 and Week 2 systems together to get another system $W$ for the two weeks together.  Then
$$
  T(W) = T(W_1+W_2)
$$ 
Properties that follow this rule are called intensive and cannot be added.

These definitions were invented for physical properties and systems and one has to be careful in applying the definitions to general situations.  I'm not sure how much thought along these lines has gone into the social sciences. 

For more, see https://en.wikipedia.org/wiki/Intensive_and_extensive_properties.