I don't know if this has been said before, but the first offense in the given period should be a freebie. I do admit to rarely quitting intentionally, for various legit and non-legit reasons, but the more major issue that I've been subjected to is losing connection or freeze. This is by no means my fault with otherwise pretty reliable hardware and internet connection and is sometimes just a small hiccup with my ISP or the game servers. But then, despite not being my fault, I'm punished and have to wait? Even though it was just a small hiccup in my internet for a reason wholly out of my control that caused just enough desync to pull me from the match, but is otherwise fine? No.
This said, I think ONLY the first offense should be a freebie. If you lose your cool just once in a while (like, once a week at most) or have a legit not-your-fault disconnect, but end up having no further issues during your game session, that's fine, we all have those. But if you're a repeat offender because you can't stay composed or you knowingly play on shoddy network connection or underspec'd hardware, despite it's affects on other players, then that's another matter entirely. I'd honestly recommend just swapping out the first ban's punishment for 0, and keep offences 2-6 the same times as posted.
I say this from having this very issue happen to me. I've had to sit out for 10 minutes because my internet service derpped out for 20 seconds, then continued strong for the rest of the night. I can't exactly change where I live if it's an issue beyond my demarcation point (somewhere between game servers and where the cable runs up to my house), so I think it's stupid if I or anyone else in a similar position gets punished for something we can neither predict nor prevent. But as I said, if it happens a second time, that's our cue that we should avoid ruining others' experience and logoff for the day/night.