If you look at the number of films and the number of developers, combined with the variation of film speed and dilutions MDC suggest can be used, it is no wonder that some, times/dilutions are way off beam. (Or in other words completely wrong). Does anyone actually believe they personally check each and every combination of developer/film, then put the information on the web for free?. It is much more likely they harvest the information from other diverse and unknown sources then, publish them as the Holy Grail of photographic truth.
Of course,sometimes they get it right, but that can be down to the fact that some combinations don't alter, or it is pure guesswork. I doubt very much they alter the setting when a manufacturer changes the emulsion recipe. In fact film manufacturers don't always advertise the fact that they have changed anything. A recipe for some gross errors when developing an odd film/developer combination.
There will be a large proportion which are blatantly wrong, as I found out with Delta 100 and FX39. It wasn't exposure error because the edge markings were as faint as the image! I put about as much faith in the complete accuracy of MDC, as I do with Wikipedia, Facebook and even some of the information on this site..