How to calculate total cost of consumption from data table as per the rate table and VAT table

[SUZZ]

Dear sir,

I am newbie to Power BI, did a small basic course from Udemy and jumped in to this world. 

Need help to solve my first ever solo personal project:

I have set up a relationship as per the picture where I have two data tables that is Electrical readings and Production table.

Season table (SEASTBL) is connected to Readings table through R-Value.

VATTBL is connected to Calender table through Year as a snow flake. Because I found only that way to connect it.

Relationship

 

In the Readings table, I calculated the KWH from many different ways: (with same results)

1) With calculated column:

KWH_CC = 'Electrical Readings'[END]-'Electrical Readings'[START]

2) With Measures:

TOTAL KWH = [FINAL KWH] - 'Electrical Readings'[INITIAL KWH]

So, from readings table, I need to calculate the total cost based on the R-value of SEAStbl, and multiply it with VAT based on the year.

I am very confused how to do it with single or multiple DAX measures?

The easy way I found is to add calculated column and do manual work like in Excel, which eventually burried the purpose of automation in POWER BI.

So, I need an expert and simple suggestion how to calculate total cost?

[amitchandak]

@SUZZ , You should get vat into the table need, Instead of calendar join with a year of tables(where you need that)

then you can have a new column your table/fact

related(VATTABL[VAT])

Or you can create a new column like

maxx(filter( 'Electrical Readings', year('Electrical Readings'[Date]) = VATTABL[Year] ) , VATTABL[VAT]) 

refer 4 ways to copy data from one table to another
https://www.youtube.com/watch?v=Wu1mWxR23jU
https://www.youtube.com/watch?v=czNHt7UXIe8