pgbench not setting scale size correctly?

Hello,
I'm trying to perform some benchmarks using pgbench. I'm using the
following rpm package:

postgresql-contrib-8.3.0-2PGDG.rhel5

for x86_64, downloaded from the pgsql yum repository for centos5/amd64.
When I init the pgbench database, the scale factor seems to work,
however when performing the benchmark I get the following output:

sudo -u postgres pgbench -c 10 -t 1000 -s 1000 pgbench
starting vacuum...end.
transaction type: TPC-B (sort of)
scaling factor: 1
number of clients: 10
number of transactions per client: 1000
number of transactions actually processed: 10000/10000
tps = 2034.588824 (including connections establishing)
tps = 2047.924715 (excluding connections establishing)

as you see, the reported scaling factor is 1, but I specified -s 1000,
which seems strange... I'm going to recompile it from the sources now.
Didn't I get anything or there is a bug somewhere?
Thanks for your help,
Enrico