Deep FX Laser is a CO2 laser which is focused into very tiny spikes designed to stimulate Collagen production and tightening by slightly penetrating the dermis. A density of 1 or 2 sounds very normal. This is how close together the laser spikes are. You don't want a very high density when it comes to deep FX so these densities are correct. The facial skin has more hair follicles and oil glands which help it heal more quickly, so the density can be higher on the face than on the neck.
The power behind each laser spike is the millijoule or mJ amount and again this can be as low as 5 for very thin eyelid skin to higher settings for thicker cheek and neck skin. The settings I use are slightly less than what you have listed but these still seem within a reasonable range. Again with the facial skin having more healing capability the power can be higher on this skin. One down side to this is you are red for a few days longer which explains your lower face redness.
Fitzpatrick skin types are also important and these basically mean the darker the skin ( Fitzpatrick Type III and Type IV) the more conservative the settings. Lighter skin (Fitzpatrick Type I and Type II) is less likely to have pigmentation problems so the settings can generally be more aggressive.
The size (1 - 7) is just how big a pattern is lasered each time you press the pedal. This is roughly in millimeters and is at the preference of the surgeon. It does not affect the result.
Improvements from deepFX alone (without active FX) are harder to see and take longer to appear as the collagen takes several weeks or months to remodel. So be sure to give the skin adequate time to heal and contract. I tell my patients we will retake photographs at 6 months after the surgery. A good indicator is the wrinkles on the lower lids since improvement here is easier to see. I often combine the deep FX with Active FX laser (Total FX) to give patients a more visible change early on. This is appropriate for those with sun damage and wrinkles. The redness and swelling takes a few days longer to go away when these are combined. It is still a lot less downtime than a traditional resurfacing ultra pulsed CO2 laser which stays slightly red for 2 - 3 months depending on the settings used. I use the ultra pulsed CO2 resurfacing laser only for severe sun damage and deep wrinkles in lighter skin types.
None of the settings you mention are active FX settings. Typically the mJ settings are 90 - 125 and the density can be from 1 - 5 again depending on skin thickness, location and Fitzpatrick skin type. I use a power of 90 mJ and density of 3 on the lower lids while on the hardier neck skin I will use a power of 125 mJ and density of 4. (At a density of 5 or greater you are essentially doing complete resurfacing like the traditional ultra pulsed CO2 laser.) On the neck since healing is not as rapid the settings must be turned way down to a power of about 50 mJ and a density of 1 or 2. Thus the ability to improve wrinkles on the neck is far less.
Finally, don't be afraid to ask your plastic surgeon these same questions. He/she should be willing to fill you in and reassure you during the post operative period. That's part of our job.