Obsolete item errors

Hello. Is there a good reason why the rules to show the obsolete item errors (658A and 013FI) are different in P13730 and P31113?

In P13730 I get error 013FI as a warning for items with stocking type O or U. But in P31113 I get red error 658A for stocking type O, and warning 013FI for stocking type U.

So, why can I add an obsolete item to a parts list, if I can't issue it in the end?

Thanks and regards.

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Hugo Pascal