You've constructed for yourself a delusional narrative about grades. Not only are they a good first-order approximation of ability, they're also indicative of

You've constructed for yourself a delusional narrative about grades. Not only are they a good first-order approximation of ability, they're also indicative of your amenability to take direction, which is more important to your prospective boss, a middle-manager in his early 30s relishing his first taste of power.