Yup. And Also every night where I sleep in my room, the cellular service isnt that great (only 1-2 bars of service too) and still extremely good standby battery time, it'll go down either 0-1% a night the most, and i been eyeing this and seeing this every single night just out of curiousity. According to your standby calculations, your only getting about 100 hours of standby ONLY in airplane mode and that you would get even less when radios are on, that is very very far off from the regular standby numbers Apple gives. my phone with all radios on wont drain in 100 hours if i dont use it as like I said my phone doesnt even go down a percent when I am sleeping.
I would say that maybe our settings differ slightly but your having 0.5% battery drain every hour in airplane mode which is just crazy
1% battery drain for you in airplane mode = in 2 hours, that equals 100 hours your 6 Plus is dead from a full charge on standby in airplane mode with screen off. Defitnetly something wrong there