When you set scoreboard like:
/scoreboard objectives add mea dummy
and add it to entities within save area of structure block:
/scoreboard players add @e[type=!Player] mea 3
than you save area with this entity and load it, pasting the same command as above:
/scoreboard players add @e[type=!Player] mea 3
will show that one entity has mea=6, but second started from scratch: mea=3.
There is exception of this for scoreboard tags stored in entitydata (which is very useful).
EDIT: It might be intended, because scoreboard objectives, except tags, are per world, not stored in the entity.
Scoreboard tags are saves in the entity data, scoreboard scores and team are saved in the scoreboard.dat, and only match that specific uuid, when a entity gets generated with the structure block it doesn't have the same uuid, but instead a different one causing the score not to be tracked.
Changing this behaviour would be a feature request (saving scoreboard scored in the entity data).