Thanks @Jennifer_Dungan , but if you see screenshot above (for 1st row of each device type breakdown), for e.g "Oppo A55" we are seeing 61 UV against 1 Customer ID. In single month its hard to believe that much re-installations.

@Jennifer_Dungan thanks for looking into this. Yes those are internal customer ids tied. We are seeing  multiple instances against same device:

Hi,   We are getting the unique visitor count via Apps is 4 times higher than the Customer ID count. which means each unique Customer is being counted as 4 unique visitors. Ideally it should be 1:1 until a user reinstalled the app.Any advice would be useful here. 

Can we use multiple dimensions in Data Warehouse? we faced issue where data was not matching between workspace and warehouse report when we applied multiple dimensions. We reached out to client support and the answer was:   1. Using more than one breakdown in DWH will deduplicate the data in DWH and...