Our geo-targeting options are around 95% accurate. This is due to a few factors. The internet ip systems are managed by ARIN.net. Each day this company allocates ips from one country to another depending on demand. An IP address that once belonged to the UK can be moved to France overnight.
In an effort to keep up with the constant changes, our network updates the IP records on our database once per week. If the service that is being used to track geotargeting by the customer is the only update once per month or per quarter (3 months) While our tracking is very accurate, their reporting will not be.
It is impossible for anyone to guarantee 100% for this matter, but we do strive to maintain around 99% accuracy with most tracking companies.