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.
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?
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.