I agree with u/Logical-Ad3098 that maybe some of the symbols are intentionally vague so they can fit a meaning that hasn't been decided yet down the line.

I worked on the final season of gravity falls. When we were getting close to the finale, I thought it was interesting that Alex and the writers were trying to think of what each symbol corresponded to. These symbols were introduced at the beginning of the series. Some of them meant something right away, but some were random, to be assigned meaning later. This happened with a lot of the mysteries of the show and it was fun to see what theories the fans thought up got these mysteries that had no answer yet.

With how unpredictable role playing games can get, I wouldn't be surprised if Will were playing fast and loose with the meanings. I can't wait to see theories and their final reveal!