DL4100 raid migration

In https://support.wdc.com/knowledgebase/answer.aspx?ID=17305
It is stated at the top of the first page that :

"When adding two additional drives to the 4 bay My Cloud, the current 2 drive RAID 1 mirror can be migrated to a 4 drive RAID 5 or RAID 10 without data loss. "

I am adding 2 - 4 TB Reds to a DL4100 that already has 2 - 4 TB Reds and do not know were I could back all the data I have, it is 95% full, so is the part about “without data loss.” True?

The DL4100 is the backup device being used.

Lets just skip that line of answers and try to answer the original question.
Is the statement, In https://support.wdc.com/knowledgebase/answer.aspx?ID=17305, made about migration true of false.

How did the migration go for you? I’m about to need to do this for my DL4100.