Can I book the B2B lookup only at the beginning of my new licence period?

No, the lookup is an etracker Analytics add-on and can be booked at any time during the existing licence period. The initial term runs until the end of the current etracker Analytics licence period and will be extended in accordance with the etracker Analytics period, unless the licence is cancelled in due time. As an add-on, the report can be cancelled separately from the etracker Analytics licence.