Hoping someone might be able to help with a questions i have...

Say for example i ended up at 120 nights in 2018 which means 60 nights will be carried over to 2019, automatically securing Diamond status for 2020, does that mean any nights i stay now in 2019 will be rolled over for 2020? so say i stayed only 40 nights in 2019, will that mean i only need 20 in 2020 to keep diamond for 2021?

Thanks