Goal

What i'm trying to ultimately accomplish is create tiered pricing based on quantities.

The client is selling different prices depending on quantity. I'm trying to figure out what is the simplest way to store, access and represent this data using fields. While at the same time i'm importing them through commerce feeds.

About my feed/Data:

I have a csv table header with columns P1 Price, P2 Price, P3 Price. Their also exists P1 Qty, P2 Qty, P3 Qty.

Thus, P1 Price corresponds to P1 Quantity, etc.

My question

Would it be simpler in the long run if i created separate fields to store each price/quantity? Or if I combined them into one field?

My primary considerations include, scalability, maintainability, etc.