I don't consider 1/32" depth superficial. That's engraved at a more than acceptable depth for most projects. At 1/32" depth you're deep enough to color fill, sand, finish, ect ect ect.
I have a very similar laser to you Kev. I engrave wood at 500 dpi, 100 power, and 50 speed on lighter woods like Alder. I take it out of focus a bit to get a darker mark. If I need to color fill with transfer tape, I run it at 25 speed in focus. This is with an 8 year old 30W tube. I have no clue what the actual wattage is but I cut Romark all the way through at 8-10 power just like you so I'd say we're on a pretty level playing field.
The big difference between the Chinese laser and the Western lasers we're talking about is the Chinese laser can run at max speed and you have power in reserve to go deeper. That's what your test illustrated to me. The 30W LS900 engraved deep enough to color fill easily. Take it a bit out of focus and you'll get a darker mark. Also remember, the original post I said 35W. That extra 5W is significant. It should allow an increase in speed of roughly 15% or simply have that little bit of extra power to make that mark just a little deeper and darker.
Equipment: IS400, IS6000, VLS 6.60, LS100, HP4550, Ricoh GX e3300n, Hotronix STX20
Software: Adobe Suite & Gravostyle 5
Business: Trophy, Awards and Engraving