su is used to determine if a job should be run (do they
have enough service units) so when a job is submitted a
'lein' is taken out from su for the maximum amount of
service units the job could consume. If the job
finishes and it does not consume all these service
units, the unused portion is refunded to su.
billable_su keeps track of the current ballance NOT
including currently running jobs, because we don't want
to 'bill' for jobs until they are actually finished.
If the user has no jobs running these two values should
be identical. I noticed that for some projects this is
not true (but it is true for many.)
This may have been caused by an old bug, so I will
sych the database up, and then do some tests to see if
I can cause the inconsistency and determine what is
causing it.
If the problem is no longer reproducable (all data
stays synched up) then this bug can be closed since it
was probably caused by an old bug that has since been
corrected.