You can make two calculations, one returning the SUM(Total Members) when it's above 1 million else return null.
And another one returning the SUM(Total Members) when it's below 1 million else return null.
Set the default number format on each accordingly, and bring both on the label shelf.
Each mark will have 2 labels, but the null one wont display nothing, and the other one will display with the expected format.
Dummy_1(mc).twbx 24.9 KB
It's not working, I tried what you asked. Attached is the twbx file, in case I missed anything.
Oh I missed the attachment of yours. thank you