Did you buy some 5/4 decking or use stuff you had around the house?
In my experience, that 5/4 decking shrinks a good bit. The last two I built, I used no gaps and cut the last board to fit.They shrunk up about 1/4-1/3". Fitting them to all work out is a good idea.
I can't tell on the end there Dave, are the posts on the corners cut off RR ties? Open on the east and west ends?
