The point that I was making is that a properly made glue laminated piece may be stronger and provide a better attachment than a "solid" piece of fir.
I think the loads at the structure of the deck and its attachments may be operating somewhat differently when you and your crew is jumping around on the deck. ;^)))
When you're done with all of the attachments and sealants, I doubt that any of these should be an issue. It looks like it fits so tight, I'd more attentive to expansion from moisture or temperature causing issues. I'm assuming that you have some "play" in there.