The CALCULATIONS DATE DETECTED is an informational column. It informs you what is the date when you should register for VAT by detecting when you first stored in a country or when you first exceed a distance sale threshold. 

These 2 triggers in the software are the legally mandatory conditions to register a VAT ID. It is named calculation date because the date when you register a VAT ID is the actual date from when we will file your VAT and from when you will be liable for VAT.

Keep in mind this is not the actual calculation date, this is only an informational column acting as a guide.