As far as I understand, the first config element in each section is the identifying key for the update. For example UPDATE .... WHERE id=101. Since you cannot determine the parameter order using  keys %{$config->{$section}}, how will this work predictably ?

Other questions are
1.. Are there updates to many records in a table ?. In other words, does the [Subcriber] section appear many times in the text file ?.
2.. Is the order in which the updates are applied important ?