T340: SATA port confusion

This is a pre-purchase question about a T340 8 drive and I am new to Dell servers.

The box is advertised as supporting 8 drives and an optical disk.

On page 16 in this doc, https://i.dell.com/sites/csdocuments/Product_Docs/en/dell-emc-poweredge-t340-tech-guide.pdf?newtab=true , the Chipset section shows for the C246 that FLEXIO supports 8 ports but under the column for the T340 only 5 is listed. Why the discreptancy? Is this document in error or is there something I am not understanding?

Also, does the use of an optical drive use 1 of those 8 ports, i.e. if I configure the box to have a DVD R/W drive, am I now limiting myself to only having 7 storage devices?