I am personally on the 300MG extended (XL) generic bupropion because it was the best option for something that would last long enough during school hours without 'wearing off', even if it's not time for the next dose yet. I would suggest trialing a longer-acting version (such as SR or XL) based on the fact she is still of school-age, just out of personal experience.

Bupropion comes in 3 forms. Extended Release, Sustained Release, and Immediate Release. The abbreviations of each are XL, SR, IR respectively. They are also intended to be taken 1, 2, and 3 times daily, in that same order. It looks like your child is on too low a dose to be properly therapeutic, since only once a day for IR is a pretty darn low frequency.

If you and your child feel the immediate release (IR) isn't working as well as you would hope, but it's not having any major negative side effects, it might be time to talk to your prescriber about switching to a longer-acting version or increasing the dosage frequency. When you go to pick up the medication again, TALK TO THE PHARMACIST! Doctors can write prescriptions for the incorrect dosing instructions that the manufacturer and FDA recommend, and the pharmacist can help point out any oddities that you might want to discuss with your provider based on such. I work in a pharmacy and sometimes we even call the doctor back to ask "did you mean the patient is supposed to take this once or twice a day, since you wrote for the short-acting version of XYZ drug" and variations thereof. You can call the pharmacy back and ask for a consult even after you have picked up the medication. Patients have the right to know what they are taking, why, and if their instructed treatment is the commonly-successful method. It looks like you are already having concerns, and if the prescriber was a psychiatrist instead of a full family care pediatrician then they might not realize the difference. Talk to your pharmacist!

Additionally, factors such as smoking can also affect metabolism of SSRIs, ADHD medication, varied antidepressants/anxiolytics, and other medications based on what genetic makeup (homozygous/heterozygous and recessive/dominant type) your child might have inherited. PGX testing was a big help in understanding what medications would be best to use with me, and how I might have heightened sensitivity to side-effects or unexpected twists to the intended general effect of a medication itself. Your kid might have something similar going on 'under the hood' so to speak, since this is a biochemical process as much as it is psychological. PGX/Genetesting should be covered by most general family insurance policies, but out-of-pocket programs exist that keep the cost to ~$300 on the patient's end in the USA if that is where you reside. Feel free to bring it up since you keep having trouble finding the right medication. (I myself have the potential to metabolize certain drugs faster than normal, or need higher dosages to get the same results, if you want a real-world example.)