Order related billing adding cleared billing document also

Hello All,

I have a serious situation. I am using billing plan on header level (Milestone) i am using milestone billing .

I have created sales order of 1 item with amount = 1000 . Now i have created milestone of 40 % (400)of first milestone and select order related billing . I am able to create first billing document successfully and sales order also showing Cleared (C)

Now when i have created another milestone of 60% (600) now the issue is billing document is adding 2 lines

40% (Already Cleared)

60%

i have already billed 40% of milestone i dont know why its adding cleared document again in billing document

Please help....

Best Regards