You have 2 accounts A1 and A2
A1=1000 and A2=1500
You create journal adjustment A1 +200 and A2 -200
The result will be:
A1=1200 and A2=1300
the script work fine but when i do the second Adjustment
A1+300 and A2-300
the logic script just duplicate the first Adjustment as it was posted in the first time and it post it again in the second time