Annex 1 is about generic SRD. The other annexes are about other bands and/or more favourable conditions for specific applications. This may seem complex and over-regulated, but there is a good reason for that :
- CEPT cares that all applications get a fair chance to access the spectrum (not just "the technology which emits the strongest signal") : for example, all Wi-SUN equipments (APs, relays and end nodes) can emit up to 500 mW (with power-control) while Lora end nodes have a 25 mW transmit power. Technical studies and simulations have shown that Lora (and siblings) would not survive if wi-sun was going to be widely deployed, and this is one reason why some parts of the bands for networked SRD have a 25 mW limitation while other parts are less constrained.
- those "additional opportunities" in other annexes are made based on dedicated technical studies (to check the impact on adjacent bands/services) that do a lot of assumptions with regards to potential/future densities of devices (because what matters if often the aggregated interference, not just the one from a single device)