LOCI - letter of continued interest. Not sure what is an EOCI
So is there anything to update? Grades are sent if they are asked for and if using the common app your school counselor should be aware to do this.
Do you have a new leadership role with a EC? Did something positive come out of some hard work you did.
They honestly want to know you want to go there and how you would be an active student on their campus.
Also follow the instructions since this is a lesson to do so. More is NOT better. If they ask for 250. Give them up to that. You don’t have to keep writing to get to 249. Don’t give grades since your sending them with your school. But if a grade stands out that your proud of then highlight that. Did you get your best grade in physics since you worked hard and got help from your teacher? This is a positive.
I would think you want this out soon also. No better way to show interest then letting them know now and not in March. Good luck.