Speculating on the nature of the observed random factor mucking things up some more with respect to physical damage, by visual inspection there is no compelling evidence that the "secondary" random factor is a multiplier, especially considering the "band" of critical pDIF between 218/272 "cRatio" and 390/241.
Suppose that the range of critical pDIF (for any cRatio between 218/272 and 390/241) is really constant (but obviously you can't observe the range without the random factor). If the random factor were really Unif(1.00,1.05) and a multiplier,
the band would widen as cRatio increases (being more obvious across a large range of cRatio), but it appears not to widen. The same conclusion is made for non-critical pDIF. 1.05 is a large enough multiplier that you would see something going on.