bob build jobs seeming too high

[Greg Troxel <gdt%lexort.com@localhost>]

I am trying to build the packages I care about on various NetBSD/macOS
version/cpu/etc. in preparation for the branch, as usual, except this
time a number of my builders are using bob.  (The set of packages I care
about varies by system, and is rapidly shrinking on NetBSD 9.)

One, NetBSD current amd64, is configured for 4 build threads, and the
dynamic section says 6 jobs.   I interpret that as 6 jobs across the 4
threads, chosen by bob as to which build gets the extra.

This particular system is a xen domU with 8 vcpus; the dom0 has 12, and
I have, for no particularly good reason, decided to hand out 8 to amd64
domUs, and 4 to i386.

It's built a bunch of things, seeming to be doing ok, but I'm seeing:

  [ 0:   8m 42s ] cmake-4.4.3 (build -j4)                     
  [ 1:    5m 8s ] erlang-27.3.4.7 (build -j4)                                   
  [ 2:   8m 52s ] icu-78.3 (build -j4)                            
  [ 3:  22m 21s ] gettext-tools-1.0 (build -j3)            

which is 15, not 6.  Not a real problem, but not what I asked for.

(I have not figured out what I want, and what's a good idea, separate
issue!  It's complicated because the dom0 disk is a shared resource
across all builds on all domUs.  So far I'm only doing one domU at a
time, mostly.)

Are others seeing this?
Am I misreading the intent?