well, first answer is the easiest. yes you will obviously see a higher electric bill. (4x65=260watts) (2x175 + 2x96 = 542watts).
so thats a little over double what you are paying for now.
second...do you have a link to this light fixture?
here are a couple things that worry me about the set up.
1) 2x96w 7100K PC lamps
-you do realize that 7100K is almost in the yellow spectrum correct? this will make things look horrible, and the algae will love it. you need actinic bulbs to replace these.
2) 10K metal halide lamps
-this is a big personal preference kinda thing. if you are aiming at a mostly softy tank, zoas/rics etc. go with 14k, 15k, or 20k MH bulbs. you are correct in the assumption that 10k bulbs could burn and/or brown out softie corals in a tank that small. but its not the fact that its more light, its just the wrong spectrum to really make zoas and other softies flouresce and look "cool".
3) tempered glass lens
-wow, i dont recomend these at all. i wasn't even aware they sold these with SE setups. again, got a link to what this fixture looks like? having a glass sheild will help to prevent water splatter from hitting the bulb. but it can also cause the light and fixture to heat up quite a bit b/c there isnt any air circulation flowing around the bulb. also, depending on how dirty the glass gets, it can cause less light passing through, leading to poor efficiency and wasted electricity IMO.
4) dual PFO ballast
- I'm pretty sure these are electronic ballasts. electronic ballasts and 20k bulbs at 175w aren't the greatest combination. but they will do. I prefer to run magnatic ballasts, or any type of ballast that will over drive the bulbs when running a 20k bulb. when you overdrive a MH bulb, it will appear less blue, but brighter. only downside is that it will decrease the life of the bulb by a couple of months.
from your description, i'm guessing this is a package deal, i.e. a already pre-constructed light canopy. and i imagine its over $500, which is alot IMO.