Sure, your model is wrong!
Seriously, double check that all of your joins are valid and complete.
Double check that the fact to dimension Logical Table Source contents are set at the correct level of detail.
Double check your keys.
The answer will be in one of those factors.
What Robert said, if your values are multiplied by 3 it means one (or many) of your joins is multiplying the returned rows.
So look at the generated physical query and you will spot which join is wrong and multiplying the rows.
I had multiple same values in one of Dimension tables, that caused my issue.
Than you very much for the effort.
That is funny, I nearly came back to the board with an additional - or the data in your underlying tables is wrong....
Thanks for your thanks, sometimes you try heard and do not get repaid with courtesy, it is appreciated.