I suspect that there are at least two effects here:

* date of reporting (see hmcclungiiii's posting - good FAQ answer for that problem) * caching

like Zach B, I have recently been seeing a mismatch between data reported from UI and API *when* and *only when* the data is for "today" (which means the most recent data from midnight PST). Like Zach, I can resolve the problem by using a different machine.

This suggests to me that Google have a multiplicity of servers under same domain name, that these machines download (every 15 minutes) some data, and that occasionally the update fails. If you use a different client machine you will probably be given the IP address of a different server system, so you access a different cache. This suggests that if you clear your local DNS cache you might also be able to reach a different server.

However, Terry's clarifying answer about specific dates suggests that the timezone issue is the root of the problem.

Cheers, JeremyC.