There really isn't any strong connection between the development times of two different films, unless they have been designed to be so connected by their manufacturer.

There is a lot of difference between the two films, so it doesn't surprise me that the development times do not follow the pattern observed in other films.

And as for Kodak's recommendation for dealing with one stop of under-exposure for either T-Max 100 or T-Max 400 (no increase of development time) that is merely a reflection of the fact that Kodak has determined that the inherent latitude of the films means that the loss of shadow contrast resulting from one stop under-exposure is less of a problem then the loss of highlight detail and contrast that results from increasing the development time. It goes without saying that increasing the development time doesn't create shadow detail that isn't there.