Reorder point calculation

Hi all !

I'm trying to implement a reorder point planning functionality.

I'm create a test (using misc.trans): 

1. +1000 items  01/07/19  (JUL)

2. -190 10/07/19 (JUL)

3  -180 10/08/19 (AUG)

4  -180 10/09/19 (SEP)

5  -180 10/10/19 (OCT)

6  -180 10/11/19 (NOV)

total issue = 910, on-hand 90

lead time = 30

I run the reorder point report, it calculated that lead time  demand (LTD) is 116.

I expected, that LTD will be near 180.

Can somebody explain me, how Oracle calculate  116 ?

Thanks

Igor