That is merely a way of saying how the tuning will end up. thats how they used examples of key levels in that post.
I will break down the blue post for you:
Mythic 0 difficulty and rewards will move up to roughly the current level of Mythic 8-10 (this is a bit hand-wavy - numerically it’s close to M10 but not having a timer at all or affixes really offsets that quite a bit).
Mythic 0 in season 4, will be scaled up to the numbers of a M+10 in season 3. (to offset gear inflation etc)
The existing Mythic+ system will pick up where that leaves off, such that a Mythic 5 in Season 4 is roughly equivalent in difficulty, rewards, and M+ Rating awarded, to a Mythic 15 today.
Season 4 mythic +5 will be scaled up aswell, the numbers in a +5 (boss health etc) are compareable to a +15 in season 3
So essentially, the key levels / scaling increases by 10 levels, if you currently can time a +15 with ease on your gear levels, a +5 can be timed in season 4 without any new gear. (guestimating here, since we dont know exact numbers)
Nowhere in the entire article do they state:
Mythic + now starts at lvl 10, and level 2-9 are removed.
Once again:
Season 4 affixes start at:
Mythic +2: Tyrannical or Fortified
Mythic +5: Volcanic or whatever is on that week
Mythic +10: affix number 3, like afflicted or whatever is on that week
Why would they introduce affixes on 2 different key levels BEFORE level 10, if it all starts at lvl 10 anyway?
Please, learn to read and understand a post before going nuts in a thread like this.\