I just looked again at your original post and realized the direction of the planks. The direction you have chosen to run the planks is contrary to the traditional method for 2 reasons. One is because it is easier on the eye to look at the long side to have the long boards running parallel to it. It's just the natural way we look at things, the growth of tree and the bark lines in general. And secondly, from a technical perspective, wood expands and contracts (moves) an average of 1/8" per foot across the grain. If your table is 4 Ft long it will move 4 times 1/8" which is a total of 1/2" . That is substantial.
Hopefully Jake Mendez will chime in and correct me or add to this.
Tony B Retired woodworker, among other things.
"Strive for excellence and settle for completion" Tony B