Are there any basic things I am missing here?
Sure. HSL is not a color space. It's just a different representation of RGB, give or take specific gamut differences which need not be discussed here. That and of course converting from a Hex code in the first place, which in itself is RGB. See the problem? Your workflow doesn't really make sense and it may make even less sense if you are working without color management or sampling your "Hex color" from somewhere without any form of calibration. I also have a hunch that you expect some color correction effect to produce a specific color when in fact HSL controls in these types of effects are offsets relative to the original color instead of absolute values. In any case, your information is insufficient to make any sense of it and you would have to explain much better what you are actually doing.
Thanks for the reply Mylenium.
It doesn't really explain anything to me though....my issue is perhaps a lot more simple than you are assuming.
My graphic designer gave me a hex value for a corporate logo color to match.
I just want to use that color in AE.
That's all I want to do.
It seems I have HSL inputs in AE (but no hex).
You can input any such info in the Adobe color picker at the very bottom whenever you open up a color input in AE. Of course in light of what I wrote in my first reply, colors will still be off. No color management and calibration, no consistent color rendering, even more so when using something as obscure as hex codes, which always reeks of "our web designer thought it looked good on his (uncalibrated) monitor.". If that is the case, then your problem goes way beyond AE and you will run into the same issues every time anyone tries to use the logo. Perhaps a good time for a team huddle and talk?
Could it just be that you're confusing HSL with HSB?
For example; 255, 0, 0 RGB red in HSL is 0, 100, 100 and in HSB is 0, 100, 50. If you enter "50" as the L value, you'll get a shade of the red hue (that is, you'll be shifting the hue toward black) rather than the red that you're expecting.
If you're still not getting the results you're expecting, try using the eye dropper in the AE color picker window on pixels of the target color somewhere else on your Desktop to sample the color (AE should allow you to sample color from any open Window).