What does this mean for 485? "based on early approval"

I checked the status of my I485 through phone. It basicly repeat the message I got from email " we mailed the document to you ......", but with a extra setence which is not in the email, said "based on the early approval of this case". Does anyone know what this means? Does this means my 485 has been approved? But I just took FP two days ago. However could they approve it before FP was taken?

Thanks!