SquashLevels is a global system and we calibrate player levels across clubs, regions and countries as best we can when we first onboard them. This can be quite a process if there a lot of results and/or they go far back in time. See this FAQ for more on onboarding.
Once we're up and running the system continues to measure and update the calibration as more results come in and more duplicate players are identified and merged. This is why your level can change over time even if you haven't played.
Sometimes we find, when onboarding a region, that the levels in a neighbouring region aren't as accurate as we'd like but we've only found out because we now have a lot more players who play in both regions and our calibration system flags that we may have an issue!
If that happens we take a close look manually and, if it really does look like an entire region is too high or too low then we will make a one-off adjustment to correct it. Anyone in that region is going to find their level changed quite a lot overnight! And they probably end up here in this FAQ!
If this has happened to you then we can only appologise. We do our best to get it right first time around but if we have limited data (e.g. no neighbours!) then we are less likely to have the initial overlap we need.
A good example was when we onboarded Australia. We thought everything was fine until we then onboarded New Zealand and then discoverd the levels in Australia were about 15% too high and had to be lowered.