RealGM

Attempting to work through the logistics of a trade that includes a player with a PPP contract.
The deal includes Jason Maxiel & Amir Johnson for Chris Wilcox
Maxiel = 1.87M this year and recently extended four more years at 5M each (last year team option)
Amir Johnson= 3.66 this year with a trade kicker
Wilcox = 6.7M
this pased on both trade checkers... ESPN shows both the PPP & TK
To my surprise it passed

My understanding of the poison pill is that you take this years salary and average it with the remaining contract to obtain the salary coming in from the other teams perspective (OKC)
Maxiel's outgoing = this years contract 1.87
Maxiel's incoming from OKC's perspective (average over 5 years = 4.37)

Can anyone explain how this trade works?

I don't really know what you are looking for. You posted all of the relevant facts, so you can work out if it makes sense from both teams perspectives. If it turns out you are just lazy, I am less than impressed; but I will show you, roughly, using the numbers you've posted.

OKC:
Outgoing salary: 6.7
Maximum incoming salary: 6.7 * 1.25 + 0.1 = 8.475
Actual Incoming salary: 3.66 + 4.37 = 8.03

Det:
Outgoing salary: 1.87 + 3.66 = 5.53
Maximum incoming salary: 5.53 * 1.25 + 0.1 = 7.01
Actual Incoming salary: 6.7

I just noticed you mentioned a TK. I'm not bothering to look up where it is, but something in my mind says it is Wilcox. Which is still fine, as long as it isn't more than $300 000. If it is on the other side, if can be up to ~$450 000. If it is larger than the allowed amount, the player could still waive it down to that level to make the deal work, if he wanted.