Hi Florian,
as far as I understand the framework behaviour, it will provide you the data even if you not requested them if they are already in the buffer. Because in this case it's not necessary to determine them again. If the data are already in the buffer depends on, if the were already determined and your transaction pattern.
In order to test if it is like this, you can set a break-point in your determination implementation of the transient data. I assume, the framework will not execute the determination if the data are already in the buffer.
Cheers,
Martin