Hey guys, thanks for continuing to post, sorry I've not been around for a bit - busy with land photography this winter season...
Brett, it's funny you mention that. Stoo suggested that it might be that exact problem. I brushed him off thinking it was impossible, because the port itself is black (not letting in any light), and the space between the lens, and the port body is soooo small that I figured it was impossible that was causing the issue.
But now here you've confirmed that it may just be that. Of course, Ikelite will not admit to that! Their housings are just perfect!
I guess I'll have to try that now too. Well, I'll be in the pool for a little while, so I'll have lots of time to play around with it, and see if I can't isolate the problem. Thanks, gents!