IIRC the Space Viking series by H. Beam Piper had ships spending hundreds of hours incommunicado in jump space. When it first appeared in the first book the story made a point of telling what the bridge crew did with all that spare time.Yes, that's my point. There are many cases of instant transit FTL, but "one week out of communication" seems to be something Marc MIller came up with to suit his campaign structure.