It's unlikely that the wires behind the wall are of equal length either, so I wouldn't consider a few feet pc cord length difference critical.
Power-wise, it' not a concern. A 10 ga wire will lose half a volt for every 10 feet at 20 amps, and since (good) power supplies can regulate within power delivery tolerances (114 to 126 volts), you will need a difference of about 150 feet to make an effect in this example.
Sonically, who knows. I'm sure some will say they have experienced or perceived a difference. And some will say they have not.