I am unsure who can explain but here are my thoughts. First sensors are critical and second I feel the LM with its limited processing power is an issue. Yes the 8640 does help a bit with floating point math.
I have read that once the LM gets in the 5000rpm range the processor can no longer effectively loop through its tasks.
The mopar tech student manual chapter on speed density is quite interesting and everytime I real it, I learn more.
MAP is #1 which is why a vacuum leak is so bad. TPS is #2, Coolant is #3 VSS is also high on the list.
I have two 87 P bodies and I was concerned with the limited power of the LM. I will tell the story of my poor gas mileage but no codes no vacuum leaks. I received codes of HEP ref, sync and all sorts of different codes on different days but could not see a trend. One day during an overboost from my MBC, the CEL was on a bit longer than normal and went away. O2 sensor was a stored code and never returned. I thought let's replace the oxygen sensor anyway since it is old...Well it fixed my poor mileage but more surprisingly it stopped all the other unrelated codes The SMEC and SBEC both have a more powerful processors and also both more advanced aux processing units. It appears they are some sort of PLCD/FPGA/ASIC devices so they should be able to control the engine better at least in theory..
As you may know, I work frequently with our ECU and all four of my LM have delaminating traces on the LM board. You can tell as the trace copper looks wavy or wrinkled. The rest of stash of SMEC/SBEC/SBEC2 pcb traces are like new condition and are of higher quality.Last winter I rewired the CSX to SBEC so we will see