It is good if your spoilboard is level but more importantly is that your spoilboard and your router/spindle be co-planar. The spoilboard and the router must be in the same plane. Using a level to make your material level with the earth is not necessary or desirable. Your material should lay flat against your spoilboard. There is nothing wrong with shimming a rough cut piece of lumber that has twist or cups so you can level it one side, then flip it over with the freshly cut side flat against the spoilboard and then flattening the second side to make the two sides co-planar. Straight boards should not be shimmed to bring them level with the spoilboard.
There are many posts here on the forum about how to tram your router to the spoilboard.
Here is one of many. Just search for hot to tram and SO5 here on the forum.
To get the spoilboard and router/spindle co-planar you adjust the router/spindle front to back and/or side to side. That will get your bit in the same plane as your spoilboard. If the imaginary line is several degrees out of the same plane as the spoilboard you get the steps you had in your picture.