It’s based on weight, the bottles just give average guidance. My girl had chickenpox and fever that wouldn’t come down (infection) so the hospital gave her an extra dose and said she’s actually allowed 5 doses in 24 hours based on her weight x
It still takes an hour for meds to kick in regardless of age. But if your little one is over talking and weighing more you could do the 7.5ml now.x
If she’s close to two and big for her age it will be fine try let the dose window get to the end before giving her more if you can x that way you can see if it helps at all more or if it’s the same x
Dosage is based on average weight