New battery is down to 76% battery health after 3 cycles

Hi i think you might have a faulty battery, maybe a manufacturing defect?, sometimes a new battery might not work well because of the manufacturing process, or if the battery have been place on sale for very long time therefore shortening the lifespan, if you still have warranty for the battery, send it back to your friend to have it exchange if possible, or if you have a friend or anyone using the same mac as you to try your battery on yours, another solution is too drain the battery to 0% and charge it up full, then check the status of the battery again, hope that helps abit cheers!