Ann: Investor briefing - Full year results to 30 June 2018, page-32

Lifetime value is calculated by:
(ACVxGross Margin%)/Churn %

66.2*81%/7.5% = $715m

The big change is due to the big change in churn. It's a significant figure but it is calculated over 13.3 years.

Essentially it is saying, if nothing is added to the ACV into the future how much gross margin will be generated given they lose 7.5% of their subscription every year, and then adding all the years up.

A big number, but bear in mind big expenses over that many years too.