Hmm, to clarify a bit more...
I didn't open this issue up to bang a few numbers into your heads, rather to start a discussion. As PE have pointed out in this thread and certainly many others in the (now found) older thread on the subject, there are many factors which affect the dev.time when changing the temperature. All of that info seems to be covered in the thread linked in my post above.
Understanding the subject a (very tiny) bit better, it certainly adds to the concept of keeping it down to as few variables as possible. I.e. try to standarize on one developer and one film, until you really know what the combination is capable of. Then maybe one more film with the same developer. The only good thing about the "recession" of analogue photography is that there arn't as many temptations out there as there used to be.

//Björn