Any renewals or Shine boutique charges that occur from the 29-31st of a month will be set to charge on the 28th day of each of the following months. This is to account for month-to-month variations in how many days are in a month.
For example: If a new Jeweler joins Premier on January 30 with a Shine Boutique they will be charged on January 30th. Then, their next monthly payment will be set to charge on Feb 28th, March 28th, and so on.
The same applies to Jewelers who renew on the 29-31 of any month.