Using Zero Work Hour tasks does not affect Percent Complete because zero work hour tasks carry no weight in the task list.
The video above demonstrates using Percent Complete Duration instead of traditional Percent Complete to understand "doneness." The calculation is Task % Complete multiplied by the duration for the summary task then divide that number by the sum of duration days.
Please know this is not the traditional method for calculating percent complete AND using Zero Hour Tasks will not help visualize Resource Allocation. We do not recommend leaving Work Hours at Zero.
Instead, you can set “Auto-populate work from duration when work is not set” in the Default Task Options
to automatically populate the Work with 8h x duration (e.g. a 5 day duration = 40 work hours)
This option will provide you with level of effort calculations based on each duration day requiring all day to complete.
Please note: I say that PMI is the acronym for Project Management International. My bad. The actual acronym stands for Project Management Institute. I'm not going to reshoot the entire video.
Duration Percent Complete Calculations
How much time should my team spend on this task?
But MS Project doesn't use Work Hours...