Doesn't gaining 600 points mean that you are able to beat the "old you" (or more precisely, people who you used to be even with) with 99% probability? I don't

Doesn't gaining 600 points mean that you are able to beat the "old you" (or more precisely, people who you used to be even with) with 99% probability? I don't know what it means in theory. In practice I win and then lose 200 points in lichess in a few days. Some time ago I used to win and lose 100 around the day in a cycle. Maybe ratings aren't adjusted around the globe, so for the same points there are different skill levels as you go through time zones. There's a fact that really annoys me: for my 2+1 bullet, it's harder to be at 1500 than at 1600. Once I'm at 1600, I can reach 1700 with a winning streak. If I fall into 1500, I tend to get stuck there.