I have the same problem, one area if you step on it you get a small creeking sound. But I can live with it. It is after all a "wood floor" and now it creaks just like at Grandma's house. Your floor is drop dead gorgeous, you did a super job on that.
Take two atta boys outta petty cash for a job well done.
Put the same stuff in my shop office (the Man Cave) and it turned out something like yours. Using some scrap left over we hammered a wagon for my grandson, he is only 14 months old, so he won't ever know it was a left over project.
I didn't use the tongue/groove in the bus, only in the office. But it was a lot __________ cheaper than $6K let me tell you. Gotta go, the Dallas Cheerleaders are on CMT ... I am outta here!