At what voltage per cell do you land? 
Now in my MinimOSD settings and Cleanflight, I am using 3.4V for warning and 3.3V for critical.

I land when the buzzer beeps (3.3-3.4V), but after landing I see 3.7V. Is that normal?

It's normal that the voltage drops under load.
I have my warning at 3.5V so i stop with full throttle manoeuvres. Critical at 3.3V for hover when i really need to come down.

It's better to stop earlier I found. 3.5v beep better stop. The more sagging the shorter the life of battery will get, so it's not worth for the extra maybe 30 secs enjoyment to shorten the battery life.

I got my alarm at 3.6V, you don't want to discharge your lipo too much if you want them to last.

Used to have it on 3.7, but I kinda know my time by now so I mostly land on 3.7.

I believe newest 14.2 BlHeli doesn't even have lipo cutoff. I've heard talks that it's not reliable if you use less than 4 lipo cells.
Anyways I don't use any cutoff at all and I get little longer fly times

I park it at or even before 3.7, and they're never out of balance when I put them on the charger.

Land on 3.7 which is when my alarm should start going off.

As a lot of the time i'm flying over concrete i don't want to risk the quad falling

When it's empty..LOL

Lol that's quite funny.. I had that a few times myself the voltage drop isn't linear and especially fast towards the end of the pack so it's easy to misjudge

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You have so much space to fly just enjoyable to watch !!

Alarm usually goes of at 3.6V then I land.