The second sentence in this section is very clear, "no licensee shall hold both a conventional and an alternative license simultaneously".  However, it is unclear whether or not an individual could hold both an interim license and a conventional license simultaneously.

The interim license will allow an individual to design alternative systems for 36 months (one time license issued sometime between the effective date of these regulations and 6 months later).  For example, if an individual receives an interim license on July 1, 2009, he/she will be authorized to design alternative systems until July 1, 2012.

The interim license does not appear to be 'qualifying experience' to become an AOSE (alternative onsite soil evaluator).  The COSE license IS considered 'qualifying experience' toward AOSE licensure.  The regulation should allow an individual to receive an interim license upon the effective date of these regulations AND, shortly afterwards, take the exam to become a COSE and hold both licenses simultaneously.  This will allow individuals to design alternative systems for 36 months AND gain COSE experience that will count toward the AOSE license.