Impression I've gotten is that the 90% of the damage is canceled by the shields, 5% bleeds through, 5% is canceled out altogether, but numerically it may be 95% canceled by shields and 5% bleeding through. I really don't care which. The point is, for science vessels, resilient shields are a must, simply due to their weak hulls.
Try out a covariant shield on a science vessel with that 10% bleedthrough and you'll find out (like I did) that you'll take a ton of hull damage despite your shields not budging much. I've actually gotten killed before without completely losing shield strength simply due to bleedthrough on a science vessel.
As a side note, I played with all different kinds of shields through Beta and headstart. As an escort, I have found these to be the hands-down best shields for me.
I had a "Goldilocks" experience with shields, with the regenerative going down too quickly and the high base shields recovering too slowly for sustained combat. These 5%/5% shields fit me perfectly, and my survivability went through the roof, with enough base shields to survive the critical "first pass" and regenerative enough for sustained combat stamina.
Hm, what do you think of regenerative Shields? I find them quite handy for my Light Cruiser. But since I am going for Science Vessel, I am not so sure about it anymore...of course, regenerative Shields regenerates fast, but they don't take a heavy burst. So, the stronger (and less bleedthrough) the better vor Science?