Fit inquiry regarding fine-tuning

I picked up a brand new MM Jailbird recently and couldn’t be happier. I think I got the right specifications, but I’m staying open-minded and jotting down notes as my body gets used to it.

Here is what I want to know: Does your device feel different in terms of fit after you’ve been lying down? To me, when I walk or stand, my flaccid penis reaches all the way to the back of the cage. However, once I lie down, there seems to be a noticeable space between the tip of my penis and the end of the contraption. It makes sense that blood flows back into the body rather than pooling in your lower regions when gravity isn’t pulling it downward, so I am fairly sure this doesn’t mean the size is wrong. Still, I wanted to check with everyone here in case someone has a more definitive answer than my educated guess. What do you think? Appreciate any replies.