There is a lot of misinformation in this thread.
Since I’ve got multiple paid/free replacements across several continents and several category of Apple products, I consider myself an expert on this subject.
1. Apple doesn’t use Coconut Battery. Their internal diagnostic result has near 0 correlation with Coconut battery. However, Coconut battery is way more accurate than any tool Apple will ever use. What I’ve seen is as battery health degrades below 100%, it actually shows a far higher figure than the real health. That’s why you only get 5 hrs with 93% health. Whereas a truly healthy brand new battery might have given you 7-8 hrs.
2. If their internal tool says you’ve lost 7% in 32 cycles, there is a 80%+ chance they will replace your battery and/or device as long as it’s still under warranty. Such a situation falls under exceptional circumstances, and if you get the right genius at Apple, they will oblige. You might need to try more than once though.
3. Keeping 2 in mind, this is 100% a reason to be worried and this is far from normal. I won’t get into the specifics, but in most cases Apple devices last the longest time on the percentage they were out of the box. If not, they stabilise quick. Even though real world usage will keep decreasing. But that’s another point. Anyway, you should be worried. And if you contact Apple enough times and properly, they are very likely to change your battery or device.
4. Do buy AC+ but if you can. There is a very high chance it will fall below 80% within 3 years. But it definitely won’t within 12 months. This is your last resort.
5. Even if Apple does give you a new 100% health battery, you’ll be back to 5 hour battery life in 3-6 months tops. This is how fast MB/iPad batteries degrade. iPhone batteries are built to a far higher spec no matter what you’ve read or been fed by everybody around you.