Hi esteemed experts,
according to B31.3, if sustained stress doesn't exceed sustained allowable, you can use the difference to increase expansion stress allowable.

If you need to increase expansion stress allowable in a particular point of the piping system to comply the code using "liberal stress allowable", have you to reduce occasional allowable (1.33*sustained allowable) in that point?

It seems that the code doesn't state anything about, so you can use liberal and occasional freely.

Any comment is appreciate.
Thanks.
Best regards

Alessio