Because the Digital Truth figures are becoming absolutely meaningless because there's no standards, in type of processing, agitation etc, anyone can post a film/developer dev times, and no-one checks them to see if they are even remotely correct.
Ian
I have been running Digitaltruth Photo since 1995, and personally oversee all entries into the Massive Dev Chart. Unlike an open forum, all data that is submitted to the chart is manually checked before it is added to the database. Whilst it is not realistic for anyone to test the actual development data of every submission, most data can be compared to existing times to check whether it appears to make sense as a useful starting point. In cases where people submit data that varies from the manufacturer's own recommendations, such data is only ever included if there is a clear reason not to trust the officially published times. Spurious data is never included.
There are clear standards set out in the User's Guide & FAQ:
http://www.digitaltruth.com/devchart.php?doc=faq
The Massive Dev Chart is used by a very wide cross-section of people, and is designed to offer starting point times in a clear and simple format. There are over 8,000 entries in the chart, every one of which has been added manually, checked and rechecked for consistency, and painstakingly maintained over a 15 year period. Thousands of hours of work have gone into this effort.
It is impractical to attempt to list specific unique agitation information for every entry. Instead, just like the manufacturer's data sheets, a standard method of agitation (initial 30-60 seconds, then 10 secs per minute - or 3 inversions) is applied. Where the manufacturer or a user who has submitted the data provides an alternative agitation technique, this is shown clearly in the Notes section which appears (where applicable) as the last column of the entry.
All development times are starting points. For reasons I don't understand, some people insist on treating a published time as if it somehow enshrined in stone. This is simply wrong. No manufacturer makes any such absolute statement. While some manufacturers provide highly tested and accurate data, others do not. In some cases, manufacturers are now taking data from the Massive Dev Chart and including it in their own published information. They have never tested it or checked for errors. Even where data is technically accurate for producing a specific level of density and contrast, unless you are engaged in a scientific use of film, development times should be adjusted for subject contrast, enlarging equipment and subjective preferences.