This is for the first oil change. The oil put in at the factory is unknown to you. Depending on who you ask they will tell you it's dino, synthetic blend, and/or may contain some lube package for engine break-in. Many like to know what's flowing around in there so put in a known product that meets their standards, whatever that may be.
I'm not sure what the computer is calculating other than miles but my oil life indicator seems to be a 10,000 mile countdown. The % oil life left seems to line up that. Those of us older guys are used to changing our dino oil as frequently as 3K miles "back in the day" so, regardless of excessiveness, many cannot go 10K miles without putting some fresh stuff in. Others us labs (like Blackstone) for oil analysis and go off of the recommendation from their report for OCI.
I only did mine early (7,500 miles) to put some of the "good stuff" in before the 10K miles were up. It just happened that I had a chance at that time (was trying for abour 5K miles but I just couldn't find the time). From here on out I'm going with ~10K miles OCI.