apt pinnig

[kitsos]

i know that pinning is not an issue in siduction cause it is deppended on sid ...
but i have a question about pinning that i have never took an answer..so i ask one
first of all i have understood apt pinning (i also used without any problem for years) but i never understand why the priority space 100-990 have to be divided in 2 defferent spaces....... 500 < P <=990 CONDITIONAL priority consideration area (if there is target release defined [P 990] the do not come in play)... 100 < P <500
      990 < P <=1000
          causes a version to be installed even if it does not come from the
          target release, unless the installed version is more recent

      500 < P <=990
          causes a version to be installed unless there is a version
          available belonging to the target release or the installed version
          is more recent

      100 < P <=500
          causes a version to be installed unless there is a version
          available belonging to some other distribution or the installed
          version is more recent

      0 < P <=100
          causes a version to be installed only if there is no installed
          version of the package

      P < 0
          prevents the version from being installed

[hefee]

The differences for 100<P<500 and 500<P<990> package gets updated
now a update to sid(501) comes with a higher version -> package get updated to the sid version
now a new version is uploaded to experimental(400) -> package is not updated

So you see the differnece is that in one case it switches to the sid version from experimental, but doesn't switch back to experimental again.