OP, I’m glad you’re proud of your son and all, but sheesh. I hope he isn’t as arrogant about his GPA as you are. GPA is just one indicator of success in any field, and it is impacted by any number of factors. Some of the most capable engineering studentx I know (more than me) have lower GPAs due to health, bad teachers, etc. I say this as a sophomore who has a 4.0 in engineering (we’ll see if it stays that way after finals next week… 
)
Imagine if everyone took your suggestion and did the longer times and got higher GPAs. (Assuming that theory is foolproof). Then companies with the “good” jobs (aka, needing a 3.7 or higher GPA since that’s what your son has) would then have to raise the requirements to 3.8+ to weed out applicants.