I've been meaning to get back here for months and have never quite got that far sorry! I hope you're all well

Our vet is fantastically knowledgeable about rats and has prescribed Azithromycin for our 650g male ratty who has been on and off antibiotics for respy things ever since we adopted him. Our vet was unable to get a hold of the normal one from their supplier and so very kindly managed to get us a human one instead. (No idea if there's some kind of a difference in the strength etc. for that reason?)
The label reads ~
200mg/5ml Powder for Oral Suspension
Powder to prepare 15ml (600mg) suspension.
Like I said he's absolutely brilliant with ratties but the doesage seems so high compared to everything that I've read online, and the vets is closed for today so I wanted to run it past you guys in case there's been a mix-up.
I've be asked to add 8ml of water to the powder, the bottle and leaflet also say this so that's all good. But I've been told to give my little fella 0.8ml twice a day for a minimum of 10 days. 0.8ml seems massive compared to any other antibiotics he's had before, and I keep reading online that they should have 8mg of this medicine so I'm wondering if there could have been some kind of confusion with ml Vs. mg? Or is there a difference between the human one & the standard one and that's why the dose is so high compared to others that I've read about? I know you give different doses for different issues but after a few hours looking I still haven't read about one this high.
Have any of you guys ever given 0.8ml or more of Azithromycin to any of your guys and gals?
Thank you so much! L.L.