We have had similiar experiences, but not because of an EXPIRE running.
We have seen very slow response to commands, in the order of minutes,
sometimes greater than 5 mins. This has happened when we have a large
amount of activity with adsm, ie a number of backups starting together
and a couple of migrations running Though I must admit if we ran an
EXPIRE it would only make things worse.
 Our problem is exacerbated by the fact that our system has very
relatively small cpus. We are running ADSM 2.1.0.13 on MVS on a
9672-r41. ADSM is not able to take advantage of the other cpus, thus we
see a severe cpu bottleneck at peak times.

Regards
Laurie de Mamiel
Woodside Offshore Pet.