> If we establish that this is a bug [...] > But I need evidence of that, and as yet I don't have it.
I don't have any evidence other than a) empirically, it fixes Joerg's problem. b) logically, it is necessary, as the leaders and the pagenumber are attached to the end of the line, so one needs to guarantee that there is enough space for them. c) aesthetically, you don't want the text in the TOC to extend all the way to the right margin, so that the pagenumbers stand out (literally and figuratively). That means that the margin for the text (= 8n) should be larger than the space for the pagenumbers (= TC-MARGIN = \w'000'). Of course the macro also needs to be upgraded to properly format multi-line TOC entries, but that's a different problem.