I need perform inter-sample calculations.

LPFTakeda

I inject one negative control and 3 samples per batch. I need substract negative control area from each sample area. I try using the following CF: 

U%.%.(CCalRef1[Area])-B%.1.(CCalRef1[Area])

Negative control has the label: B0x (x= correlative number associate with each batch)
Samples have the label: U0x (x= correlative number associate with each batch)

With that, I get substract negative control area from the last batch in my sample set to the all batches in my sample set. I want to substract each negative control with its corresponding batch. 

How Can I get this? 

Empower2019

The way to do this is to keep the same label for your negative control no matter how many times you use it in your sample set. If you have 10 control samples, label them all as B. Then keep your unknown label system as you have it..U01,U02 etc. Then change the formula to 
U%.%.(CCalRef1[Area])-B.1.(CCalRef1[Area])
In Empower inter sample calculations, the software will always use the most recent label in the sample set to calculate any unknowns that follow it, so the first B will be used to be subtracted from the subsequent unknown samples, then when Empower encounters/processes the second B, it uses this B to subtract the unknowns which follow it, and so on throughout the sample set.