I do some test in Windows (delphi)

using ReadCommitted + No_Rec_Version + Wait
I get very low dead lock,
first attempt 10 process = 150.000 update = 2 deadlock
scnd attempt 10 process = 150.000 update = 0 deadlock

using ReadCommitted + Rec_Version + Wait
I get very high dead lock,
( I stop the test because the higher deadlock )

So I think the problem of Alessandro il the lock mode
and he must trap the deadlock error and perform a Rollback
before attemp to reupdate with the same data.

Best regards
Marco Kregar