Recursively calculate diff between dates for customer contracts

Hi Anonymous 
Here is the sample file with solution https://www.dropbox.com/t/pbCv6QBPPQp0LhAy
The table looks like this

You need to create an order column:

Order = 
VAR CurrentID =
    Contracts[Id]
VAR CurrentStartDate =
    Contracts[StartDate]
VAR CurrentIdTable =
    FILTER (
        Contracts,
        Contracts[Id] = CurrentID
    )
VAR Result =
    RANKX (
        CurrentIdTable,
        Contracts[StartDate], ,
        ASC
    )
RETURN
    Result 

Then the difference column

Gap (days) = 
VAR PreviuosEndDate =
    LOOKUPVALUE (
        Contracts[EndDate],
        Contracts[Id],
        Contracts[Id],
        Contracts[Order],
        Contracts[Order] - 1
    )
VAR Difference =
    DATEDIFF ( PreviuosEndDate, Contracts[StartDate], DAY )
VAR Result =
    IF (
        ISBLANK ( PreviuosEndDate ),
        0,
        Difference
    )
RETURN
    Result

Please let me know if this satistfies your requirement. Thank you