I think I phrased the question wrongly: Does having a more dilute developer and therefore longer development times give a greater timing latitude?
I'm not familiar with Delta 400, so let's take HP5. I would develop for 5.25 minutes in dil. B, and 10.5 in dil. H. The difference of a quarter of a minute at dilution B can really change the negative, because HC-110 is so active. Is this effect lessened by greater dilution?