Hey Kamie, sorry but was out on the boat today.
For the most part Hellraizer is spot on man. It does sound like your buddy knows what he is doing. Although, if you have 240v outlets then you are probably running your ballasts on 240v. A 1000w ballasts uses roughly 9.5amps at 120v and 4.75amps at 240v. 120/240v is just the force at which your electricity is delivered. If you have twice as much force (240v) then you need half the draw (amps). This doesn't affect your electrical bill though because you are still using the same amount of watts. Electrical companies bill for kilowatt hours. They do not bill based on your amps. The reason for using the 240v lines is that it allows you to use less draw off your main panel. If you have a 100amp service for example and you put everything on 120v service in your house then you wouldn't have enough room on your main panel. Large appliances have significant draws (a/c, electric stove, hot water heaters, etc...) so they are put on 240v service.
As far as your setup goes; do not worry about your equipment being 110v and the outlets being 120v. It's the exact same thing; same outlet; etc... It's totally normal.