I'm looking at the technical specification of this guy: MacBook Pro (13-inch, 2017, Four Thunderbolt 3 Ports). They say its weight is 1.37kg, but with a note: "Weight varies by configuration and manufacturing process". So how do I know how much it weights e.g. when I choose different processor? Is there any difference in weight when using Core i5 vs Core i7? Or when using 16GB RAM instead of 8? And what does it mean "by manufacturing process"? Thank you in advance for any help.