I believe you are looking the difference between Tracking Area and Location Area, and knowing this you can make a guess of the LAC and TAC :)
Location Area
As far as I know location area is GSM and UMTS concept. A "location area" is a set eNodeB that are grouped together to optimise signalling. To each location area, a unique number called a "location area code" is assigned. The location area code is broadcast by each eNodeB at regular intervals.
Tracking area
The tracking area is the LTE counterpart of the location area and routing area. A tracking area is a set of cells. Tracking areas can be grouped into lists of tracking areas (TA lists), which can be configured on the User Equipment (UE). Tracking area updates are performed periodically or when the UE moves to a tracking area that is not included in its TA list.
Operators can allocate different TA lists to different UEs. This can avoid signaling peaks in some conditions: for instance, the UEs of passengers of a train may not perform tracking area updates simultaneously.
