Yes it can even be the only way ! I just realize that if you just ignore this case, like your patch, you're will loose the previous value which is not in the audit table ! Is this the choice you've made in your company?

Yes. We're not particularly fond of this side of the equation, but we did so for good reasons. The main one was that we offer our product in SaaS and the we give our customers the run-time ability to tune audit configuration – each enterprise may have different needs and sometimes they require that some data is not retained or not retained longer than X. In this case it would not be possible to ensure there always is some previous record.