This trouble shooting guide refers to how to correctly transfer a Zucoins wallet to a new phone.
You can not transfer a wallet from one phone to another via the phone transfer process; otherwise, the Zucoins Wallet PWA app could be ghosted (copied) by hackers.
Same with banking apps that require authentication when moved to another phone.
The best way to do this is to have a backup of the wallet from the old phone, and once your new phone is set up restore from the backup using a new wallet loaded on the new phone.
When you restore from backup it will reload past transactions and contacts that had been entered prior to backup.
Any transactions after the backup will of course not be recorded.
However, as the SplitChain network has your true balance, based on the latest two transactions (it does not keep all your history) it will update your wallet with your latest balance.
So you would backup depending on if you wish to keep all transaction history or just to know it will restore your true balance.