Hyperthreading is free to be used by the CPU. WaveLab does not change this.
In the past, WaveLab was offering to execute as many tasks in parallel as logical core. Now, and for the better, the propose number is limited to the number to true cores. For someone not specialized in multitasking, this could seem a regression (“I can’t run as many tasks in parallel”), but in practise, this is better for the overall performance.
Understand that even on a 4 core machine, WaveLab could allow to run 100 tasks in parallel. But this would be slower, globally.
Hyperthreading is just a CPU trick and its interest is reduced, or even becomes a regression, when too many independent tasks are running in parallel.