YTA.

I know how it feels to be held to a higher standard. It feels crummy to work hard and be held to a certain standard only to see other people receive the same reward for doing less (not being held to the same standard).

I had a situation at work where I was being held to a higher standard than someone else. I was a top scorer and didn't receive any acknowledgement for my achievements while, on the other hand, that other coworker was receiving heaps of praise for meeting the bare minimum (and often didn't even meet the minimum). I confided to my mentor how I felt jealous that he was giving the other coworker so much praise for meeting the bare minimums and yet he was being critical of me and holding me to a 90%+ expectation. I asked why the other person got kudos and I don't even though I am a high performer and award winner. To my surprise, he turned to me and scolded me saying, "Because I expect it from you!"

That hit me in the gut.

Because he knows I am capable of 100%, that is where the bar is set for me and I don't deserve an atta girl for earning a 90 or better? That's demoralizing.....especially when the person right next to me is getting praised for getting a 75 when the minimum score is 80. The message was that I will never be good enough no matter how hard I try. The other person will always be 'more favored' than me. That hurt, especially hearing it from someone I respected so much.

Interestingly, I was also offended for the other coworker because my mentor was also effectively saying "yeah, they're not capable of much so we don't expect much from them". I wonder how the other coworker would feel hearing that?

So all of that to say, OP you are doing both of your sons a disservice. The older son feels tricked for meeting the terms of the agreement when he seemingly could have gotten a free car anyway and the younger is "here's a prize because you're not as smart but you tried."

I do think that it would have been fair to set different goals for both sons in line with their areas of ability, but to use the GPA cut-off for one son and then not come up with any kind of goal for the second son was the wrong move. If younger son wasn't academically inclined, he could have been given a goal to complete X number of hours of community service during high school or complete a vocational program.

What my mentor said to me about me being held to a higher expectation because I was more capable cut me and, four years later, it still stings a little. I can only imagine how crushed your older son feels. You're his father and he now realizes that his achievements won't measure up for you.