If I configure a tree of services the system will start populating the reports only from the moment i submit the tree itself, ignoring the old trigger data.

I understand that this is the default behavior, which I think needs adjusting (I'll open a FR ) but there's an important issue:

If someone opens the SLA report and sets the time option to "Last year" he will get a nice 100% OK, which is wrong.

The Services page should report "No SLA data available for the period" instead