Alternative data for the loop

Hello,

I am writing a script for data analysis and I am not sure how to design the loop. I have XLM document with results of different measurements where first measurement is the base and every next measurement is using this data. e.g.

1. measurement_1
2. measurement 1 * measurement 2
3. measurement 1 / measurement 3
4. measurement 4 - measurement 1 etc. etc.

It may happen that the base measurement has to be repeated in the middle of my test (let's call it measurement 1_new) from now on, for the following measurements (and respective calculation) I want to use measurement 1_new. I.e.

1. measurement 1_new * sqrt(measurement 5)
2. measurement 6 / sqrt(measurement 1_new)

I was thinking about looping it before each and every measurement to check if measurement 1_new exists but I feel there must be simpler way to do this. Do note that I want to use measurement 1_new only from the moment when it exists, not for all previous measurements. The measurements will be saved in the exact order.

I would appreciate some good advices:)

K.