I have to admit I never use programs one or two but have done well using the rest of them, although I stick to the hot program most of the time although that can take some getting used to.
There's so many variables that could be affecting depth (both ground conditions and settings) it's hard to give any meaningful advice, especially since the Deus has so many available customizations, but be assured the Deus will go as deep as your 800 or any other detector once you get the hang of it. Using both the X35 11" and 9" HF coils I regularly find targets at 8 to 10 inches and more depending on the program and frequency, sometimes very small targets even when surrounded by lots of hot rocks, trash, and rusty iron.
Even if you set the recovery speed as low as it can go the Deus is a very fast machine. Keep experimenting with the different programs. The pre-set programs were very well thought out and should work well even without using the expert settings, at least until you get the hang of it.
If you haven't already, read The Deus Handbook by Andy Sabisch. Lots of worthwhile tips.