IPhone 7 - Speakerphone issues.

I have gone through two different iPhone 7's in the past month, both have had the same issue. I use speakerphone for 90% of my calls. During 50-60% of the calls (using speakerphone), the person on the other end says they "can barely hear me." I then take the phone off of speakerphone and put it to my ear (which I hate to do). The person on the other end can then hear me. I tell them I'm having trouble with my phone, and ask them to describe what I sounded like a moment before. They always say I sounded like I was 10 feet away from the phone, one woman said I sounded like I was "talking to her from across the room." 40-50% of my other speakerphone calls communicate perfectly fine.

This is making me contemplate whether or not I can keep the new phone. I depend on speakerphone, and it's just not working. I've called AppleCare and gone through that rigamarole. Hard restarted the phone, restored the phone, removed microphone access from any apps which could be interfering. The case is not covering any of the microphones or speakers. I've considered buying the iPhone 6, however, if it's an ios10 issue, it could affect that model as well.

Very annoying for a $900 device. I would expect the simple things to work. I have until 10/17/16 to once again return the device and go back to my iPhone 5.