Conditional Top 20

[fabo]

Hi everyone. 

I have this scenario: 219 plants ("Production Unit" or "PU") are located in 15 geographical regions. They produce only one product in different amounts. Data is collected monthly. Visually:

 The data model is the following:

What I need to do is a "PU" Top 20 (Plant Top 20) in chart 2 (chart in the right side) only if there is no Region selected in chart 1 (chart in the left side).  If there is at least one Region selected, then chart 2 is simply filtered by that Region showing only the plants located there.

What I did

I added a calculated column in plant table (T_PU) named Rank:

Rank =

RANKX(

 ALL(T_PU);

 CALCULATE([Sum of Production])

)

And these measures:

Sum of Production = SUM(FT_Production[Production])

Production by PU =

IF(

 [No of Selected Regions] <> [No of Total Regions];

//This is True when at least one region is selected

 CALCULATE([Sum of Production]);  CALCULATE([Production Top 20])

)

No of Selected Regions = DISTINCTCOUNT(T_Region[id_region])

No of Total Regions =

CALCULATE(  DISTINCTCOUNT(T_Region[id_region]);  ALL(T_Region)

)

Production Top 20 =

CALCULATE(

 [Sum of Production];

 T_PU[Rank] <= 20

)

What I got...

Two issues:

1. A quasi-Top 20 chart. 

The Top 20 chart seems to be ok but.. The order is not quite right:

2. When a Region is selected the resulting chart only shows some plants (in some regions, it shows no plant at all).

Maybe some of my steps are not appropriate. Or maybe I need a complete different approach. Any suggestion will be welcome.

Regards!

Fabo