Its been a while since I did the testing. Are you able to show that a conscript unit suffers more suppression than an elite unit for a given amount of incoming fire with all other factors being equal? Following on from that, is a conscript unit easier to pin than an elite unit? In fact you can test this for all the soft factors (Leadership, Motivation, C2)
In my testing I don't recall seeing any difference in the amount of suppression from a given amount of incoming fire between different units of differing soft factors. Only the effects on morale and the time to recover from the suppression were noted.
I have noticed Pinned troops still returning fire although at a much lower rate than unsuppressed troops. The only time troops will not return fire is when they are Shaken or Panic'd. So you could make the argument that troops are not 'fully suppressed' until they are Shaken, which means that troops with higher soft factors are harder to get into this state.
Another interesting thing I found is that suppressed troops won't fire on an enemy jeep, unless it comes within 30 metres... suppressed troops will fire on enemy infantry in the open from around 100m (sometimes less), but apparently jeep passengers are safe.
@Bulletpoint I wonder if this is related to the halftrack situation where AI infantry generally will not fire on a buttoned halftrack. IIRC the AT team will fire at about 150 meters but as long as the HT stays buttoned the rifles, SMGs, & LMGs will hold fire until the HT approaches to under 32 meters. A jeep does not have un-button (Open Up). Possibly a jeep with no MG is treated like a buttoned halftrack. A jeep with a MG (which is always manned as long as 2 or more troops are in the vehicle) is treated the same as an un-buttoned HT with a troop manning the halftracks MG.
@Bulletpoint I'm afraid I don't know the answer to that one. It's unlikely that I would do more testing on this subject to delve deeper primarily because my own curiosity has been satisfied and my gameplay adjusted accordingly now that I understand better what is going on under the hood.
If someone does get around to testing this out for themselves then I'd be interested to know the results.