Mugur,
your explain seems to show the number of A or B have changed or have been updated.
But, it is curious the number of A or B or values in A or B could change so fast (between the two report)
What are A and B ? Does it make sense the number or values in A or B change so fast ?
May be this problem need a support case to avoid any misunderstanding and investigate with the exact SUM...
Best regards