The TTMRA is a one off conversion. If you converted your CASA CPL to a NZCAA CPL you will be unable to convert a latter gained CASA ATPL to NZ
Well, it works the other way. Or used to.
I obtained an Australian CPL via the TTMRA. Never used it. Later got a job in Aussie sometime after getting a NZ ATPL. CASA issued me an ATPL no worries.
Maybe its to stop Kiwis avoiding the flight test.