When you hover your cursor over the print on the Live View (to show the properties for that print), you said it shows the correct size there.  Hovering over the white space on the page shows you the page properties, so that sounds good too.  Since you said the correct size is shown when you hover your mouse over the print on the Live View but you end up getting a print size that differs from that, it means the issue is in the driver.  Since the print properties in Live View show you the exact size that is sent to the driver, whenever you get an actual print that is a conflicting size, the driver is modifying the print size (internally).  The only exception is if you have a non-zero value in the "Canvas" entry on the Settings tab but I'm assuming that is zero.

In most cases, the cause is a reduce/enlarge checkbox in the printer driver.  Click the "Properties" button on the Settings tab and go through the printer driver options and be sure there are no options that are set to reduce or enlarge prints.  Also make sure borderless is turned off if you want exact sizing but I doubt that is the problem here because borderless printing typically causes larger print sizes, not smaller.

Regards,
Mike