Referring to rows in one table from another in a calculation

[#1]

Hello,

I would like to create a simple app to choose the best from a table of tariffs for a list of users, based on each user's usage.  Example data with illustrative Excel calculations is attached.  Essentially, the users and their details are in one table and the tariffs are in another.  What I can't figure out how to do is to refer to each row of the tariff table to calculate the cost on that tariff for each user.

I have tried to do this using Qlikview 11, but Sense would be fine if you prefer.

Any suggestions?

Thanks!

Leo

[#2]

OK, I think I have found the answer in the "Inter-record" functions, particularly FieldValue and FieldIndex.

However, I would still like to be able to display a count of the numbers of users on each tariff... !