Hello,
To be clear, the user IDs (not the user names or user logins) can be different if you import them into your new MySQL because the id is an AUTO_INCREMENT column. If you have 100% certain that you have preserved all the IDs then there should be no issue.
The procedure I described above, with the intermediate CSV files is available so that you do not have to worry about IDs. The plugin normally associates transaction rows in the db with user ids. When the transactions are exported to CSV, the user ids (account column) are replaced with the user emails. Upon import, these are again replaced with the user ids, which can now be different, due to the behavior of AUTO_INCREMENT columns on MySQL.
I did not understand from your post. Did you perform this exact procedure?
1. Transfer the full WordPress backup to a new server.
2. Export the transactions to csv from the old installation, one csv file for each coin.
3. Clear the transactions table on the new installation (with DELETE or TRUNCATE commands)
4. Import the CSV file or files to the new installation.
If you have performed these exact steps and the problem remains, select a user whose balance is not correct and look at their transactions. How do they compare to their transactions on the old installation? Are there more transactions? Less? What’s going on?