I knew the L87 DFM had different operating configurations than just V4 and V8 mode; but didn't realize it could be any number of cylinders with seventeen potential firing orders.
That just sounds like an overly complicated system.
I actually have some experience with INCREASING the V4 mode duty cycle in a '12 Yukon XL.
The same 4 cylinders shut down. The changes I made caused those 4 cylinders to carbon up, eventually increasing oil consumption.
That problem, is that the shut-down cylinders eventually cool, which also limits how long an engine can stay in V4 mode.
(Very early Chrysler V8s pushed their V4 mode duty cycle a wee lil bit too long, cracking engine blocks from cylinder temp differentials.)
Dynamic Cylinder Mgmt (I know) can disable any (or potentially EVERY) cylinder.
So when it goes into (for simplicity's sake) V4 mode, it varies which cylinders stay on or shut off constantly.
This helps to maintain cylinder temps, reducing carbon buildup, which is a good thing.
Ultimately the weakness of these iterations of cylinder deactivation engine remains the dual-mode lifters.
The variable lifters simply cannot be built to withstand as much / last as long as one-mode lifters.
No matter how much more it would cost GM (or any other OE, for that matter) to improve on the specs / design hardware,
be sure that they will NOT do it.