If anything I think you should increase your feedrate a bit. 10ipm at 18000 RPM on a single flute grants a chipload of 0.0005", which is kinda the lower limit in my book, and depending on the sharpness of your endmill it may be dangerously close to rubbing (did you get nice little chips flying out during the cut ?)
DOC on the other end, I like to use 10% of the endmill diameter for regular (non adaptive) toolpaths, so I would probably decrease yours from 0.05" to 0.015", if that works better you can then re-increase it incrementally.
The Z-plus and HDZ definitely help to get good results/finish in aluminium, but they are not mandatory either, not at those feeds and speeds (i.e. they shine when starting to push things to more aggressive settings)
Check out the great MaterialMonday videos, there are several where Winston recommends settings for cutting Al.