Dear Banana,
You've got some great questions and I'm not probably the one to give the best reply but I've read some GREAT!! stuff on this site. I suggest you search under fat and ketosis to see if you can find them. Allow me to briefly attempt to paraphrase some of the main points:
Ketosis is an indication that your body is burning fat for fuel! This could be your own fat reserves or dietary fat... which is why the eskimos are still around
The metabolic advantage of burning fat for fuel are 1. appetite suppression 2. burning fat does not necessarily release all the calories that is possible. When the body burns fat it can stop at the fatty acid level and use these for cellular repair and such or simple discard them in your urine... hence the strong suggestion of Boatloads of water. You would prefer the body to use what it needs and discard the rest as unused calories. Hence the "metabolic advantage" of eating lets say 500 cals of fat but only processing 250.
You certainly can eat more carbs and lose weight but if you eat to the point where the body now can burn carbs (it's first choice) then the metabolic advantage of burning fat is lost and you run the risk of if you're eating too much then dietary fat can be stored as body fat. Therefore as you increase your carbs the more critical it is to look at your caloric intake, exercise level, and metabolic level.
I like the freedom of not counting calories and if I'm hungry I eat something so I stay pretty close to induction. However, the point about the body adapting is genuine. Evidently when you decrease your source of fuel (whatever it may be) to get your body to burn reserves it does sense that "lean times" are here and it depresses you metabolism. That's why exercise is critical. To try to keep your metabolism up. And like someone said above, the body is highly adaptable. If you swim everyday the same amount, your muscles will "learn" how to efficient and you will burn less cals than when you first started. Atkins warns about using this diet as a quick fix and how it could stop working for you (body adaptation again) search for that thread under the "wrong way to do atkins.
Sooo... With all that Here's my finally take. If you're feeling deprived by all means try to up your carbs a bit. And if I may suggest spacing them out as much as possible. If you're going to try 40 don't pile them on in one meal. Make sure you're eating enough protein and enough fat. Remember fat has a metabolic edge to LC'ers by tricking the body into thinking that it's getting more calories than it actually processes and suppresses appetite.
I'm trying not to worry about maintance. I'll worry when I get there and besides when I'm really slim I know that I feel like exercising a lot more (I tend to live a more active lifestyle) so that will help. And lastly, I've personally decided that I just don't want to fight my weight any longer. I'm _tired_ of yo-yoing and for the first time, I'm willing to accept limitations on my food in order to stay in check.
Good Luck and search this site. It's a tremendous resource!