There's no underhanded 'fiddling' of the ISO speed by devious film manufacturers. It's just the way that ISO film speed is measured that gives a slightly optimistic number.(posted 8201 days ago)
What else do you expect from a specification 'designed by committee'? Like most other standards bodies, I'm afraid they don't appear to know which part of their collective anatomy is for bending their arm, and which part is for sitting on.It's when the box doesn't give an ISO speed at all that you want to get suspicious. For example; TMZ3200 isn't 3200 ISO, or anything like it. Nor would the ISO speed of Delta3200 or Neopan1600 be anywhere near to their implied EI ratings, if they were tested according to the ISO methodology.