Two seperate mailing lists?

[yourcablestore.com]

If I subscribe to my mailing list using the 'Subscribe to our Newsletter' box the e-mail addresses is added to Mailing List - All. If the e-mail address is already a registered customer it does not update the customer or put the e-mail address on Customers - On Mailing List. Also the Maillist check box on the customer's detail page is left unchecked.

If I subscribe to my mailing list by checking the 'Yes!, I would like to join your mailing list' check box the the e-mail address is added to 'Customers - On Mailing List' and the Mailist checkbox for the customer details section is updated but the e-mail address is not included in Mailing List - All.

Is this the way it is supposed to work? The two lists are completely separate? Is there anyway to sync the lists?

I could send out the newsletters to both groups but i am worried this will send two e-mails if the customer subscribed to both lists unintentionally.

I am also worried this will lead to confusion on the customers part. Example: customer enters e-mail address and clicks unsubscribe from the 'Subscribe to our Newsletter' box but it doesn't remove them from 'Customers - On Mailing List' because the customer used the check box during checkout (or the check box in their account) to sign up and they continue to receive newsletters. Or the other way around customer thinks they are unsubscribed because that is what is shown in their account but continues to receive newsletters because the customer signed up using the 'Subscribe to our Newsletter' box.