I've heard all that too, but when you hear that advice they never couple it with what time you should get out of bed or go to sleep. It also doesn't take in to account the life of a 3rd shifter. Last Christmas I was exactly where you stand today. I have lost 90+ pounds in the last year and what I know to be true is that if you eat fewer calories than you burn, you will lose weight over time. That whole 6:00pm nonsense is to keep people from raiding the cupboards all evening long while they veg out in front of the TV. And I'm certain for some folks it's a great diet technique, simply because they do tend to overeat in the evenings.
Personally I would not eat a Powerbar over having a well made nutritious dinner. There is nothing wrong with Powerbars per se, it's just that they don't taste better than a real meal and fairly soon you will get burned out on them and maybe fall off the wagon. Also eating a Powerbar instead of eating dinner with your family isn't great for the kids.
The best advice I can give you is to measure your portions and make sure you are logging them correctly, not just eyeballing it. The other thing you want to make sure is that you are getting enough protein and drinking enough water, 64 baseline + 8 oz for every 10 pounds you want to lose. When you workout, you break the muscles down and they need protein in order to repair themselves.
Starting weight: 244.6 lbs. 10/01/09
Pounds lost: 80.6 lbs
Current weight: 164 lbs
Goal weight: 120 lbs
Weight to go: 44 lbs
Goal Date: 1/1/13