Thanks Gurunath for your reply and helping nature.
However, does your answer really make any sense ? in OVA8 oldest open item is not checked so in this case system does not bother about the oldest open items but you mentioned it could be the reason.
And more over there are no over due items for this customer which you can observe with my above replies.
Please note : these kind of replies really does not improve the SCN standard.
People will check with friends and colleagues if not resolved then post it in SCN still here if it not resolved at last as last option will reach SAP company by raising notes.
So that is the standard of SCN.
When we are giving answer at lest OP should think that yes that could be one of the reason but not entirely irrelevant.
Please don't misunderstand my reply.Hope you understand in positive manner.