Understanding A3 AND A4 LTE event UE measurement report?

Question

I understood A3 and A4 in the following way -

A3 event - UE measures both serving and neighbour cell?
A4 event - UE measures only neighboring cell?

Please correct me if my understanding is wrong.

Comments

A3: Yes, Ue mesure both Serving neighbor cell but with the following condition:
The LTE Event A3 is triggered when a neighbouring cell becomes better than the serving cell by an offset. The offset can be either positive or negative. The event is triggered when the following condition is true:

MEASneigh + Oneigh,freq + Oneigh,cell - Hyst > MEASserv + Oserv,freq + Oserv,cell + Offset

A4: yes, Ue measures only neighboring cell but with the below condition.
When  a neighbouring cell becomes better than a threshold.

MEASneigh + Oneigh,freq + Oneigh,cell - Hyst > Threshold