In the TMMi framework, specific goals can indeed have different specific practices across maturity levels. The practices associated with a specific goal evolve as an organization matures, reflecting the need for more sophisticated approaches at higher levels of maturity. For example, test design practices at Level 2 are more basic compared to the more comprehensive practices at Level 3, which include integration with other lifecycle processes.
The other statements are incorrect. For instance, sub-practices are informative and not mandatory, and while generic goals have the same set of practices across process areas, specific goals vary by maturity level.
TMMi Reference:
TMMi process areas include specific goals that may have different practices depending on the maturity level, as the process areas evolve with higher maturity.