I sent all of my scores to Stanford, but I forgot to self-report all of them on the Common App. I only self-reported my highest ACT and subject tests. Is this an issue?
No. They have your scores officially.
If I remember rightly then the Common App only asked for your highest scores…But if you scores have come from CollegeBoard then I’m sure it won’t cause too much of an issue
Stanford requires all ACT and SAT scores, but you can provide whatever subject trest scores you want to provide. Also, what it allows with ACT is that you can send one official test score and self-report other ACT tests on the application, and then you will be required to submit other official ACT scores only if admitted. It does that because it knows ACT charges to send each individual test while SAT will send all in a single order. You can however choose to just send all the official scores rather than providing them on the application, and what you have done is fine although it cost you more than necessary.