Load does not equate to boost. Though load and boost are related as boost typically increases as load increases..you can still be under a lot of load, with very little boost if say your turbo wasn't spooled up yet.
If it was boost vs RPM then we would have labeled it so.
I'll let Henrik explain the details.
I will say, one of the cool things about the Rtek is the ability to log what timing cell the ECU is using. You can log the "Timing Table" parameter, listed under "Table Indexes" on the Select Param screen. This will log the RPM and load cell numbers of the cell the ECU is using for it's timing calculations at that moment in time. You can also do the same for the Fuel Correction table. If you make a log and, say, you see a spot that you're running lean, if you logged the Fuel indexes, it makes it stupid easy to see which cell you should update.
Hmm, this just gave me an idea.