Yeah Buzz is right.
If you've updated the GamerScore to Xbox Live, even if you edit your profile with profile eidtor and remove achievements etc., when you go back on and connect to Xbox Live it will automatically revert all the gamerscore you just removed.
But I mean, if you make sure everything is in order, and nothing seems fishy, you SHOULD be alright.
Can't just inject original profile if xbox.com has been updated. It won't let you connect to live because the profiles don't match.
I have an idea but am at work so can't test it. Okay game adder makes a modded profile. I opened it up in a hex editor and it has a list of games. These are the ones that it adds. What if you deleted them then opened your original profile in hex editor. Copied the game/achievement section and pasted it into the modded profile where the game list was. Save then used hash bock calculator and injected the modded profile. And then followed the same steps you used to add games. Wouldn't it update xbox.com like it did before but this time with your old information.
Did anybody actually read that post? The whole thing? You can do that but then earn one achievement and your gamerscore comes back. xbox.com has your played game history to really lower your gamerscore you would have to somehow mod that to get it lower.