@nychan, the devices only report changes in temperature or humidity, if there is no change there is no report.
For example, I understand that you have configured (300sec Max Interval and 50 for trigger Temp change).
your device will inform of any change between 0.1° and 0.4° every 300 sec and changes of >= 0.5 ° since previous report, always.
If you only need to see changes >= 0.5° then you must be configure the Interval report to 3600 sec or more. In this way, the predominant trigger of the report will be the condition >=0.5°.
You only will receive reports of less than 0.5° if the 3600 sec passed and there has been a change <0.5°.
I do not know if I have explained well, any questions tell me.
A graphic example in case it helps someone to clarify