One of our customers asked us for help to solve a sales tax problem. He said that there’s an issue that if you set up tax by zip code, if the customers enter their zip+4, it won’t charge them any sales tax.  According to our research, in order to address this problem, we have to created an extra zip code entry with the wildcard for each zip code in the table. For example, to charge sales tax on zip code 90012 and any extension within that zip code we have to add 90012 and 90012* to the table. Once the additional entries are added, sales tax for any zip+4 will be charged at the zip code level.  To eliminate the problem of  WooCommerce not charging zip+4, we will be working on a new version of our zip code level sales tax rate table.  The changes will be reflected in the next update.