No, sorry. The resource leveling command will never alter assignment units nor assign resources. Its only job is to move tasks so the resource's Peak Units are less than or equal to Max. Units.

Assign your resource at 100% to task A to get the 8 hours of work done in one day and then assign at 100% to task B to accomplish to 32 hours of work in 4 days. We are not as efficient at multi-tasking as we would like to think