After Effects Opacity behaving differently from Photoshop?
I think it seems like you have added layer style to the text in Photoshop. The text in the photoshop has Bevels &amp; Emboss. From this point, you may have some other effect added on this text layer. I tried myself with same red background and same white text, here is what on my computer:


Here is what it looks like in AE of 20% opacity:


And here is what it looks like in AE of 40% opacity:


So I think, it's only about how the software distribute the percentage of opacity, in After Effects, you should assign a higher opacity to the layer. I don't think there is a wired problem that in AE that you got a dark layer as you stated. 

Hope this may help :)