Forms :: Search Data On Basis Of Date Range?

i create form on which 3 window, 3 Canvas, 3 blocks are there.

1)first block contain 3 items from_date and to_date(nondatabase)and find button

2)second block contains 3 items segment1, quantity and payment_terms

when i enter 2 dates and click on find button 2nd window open. segment1 and quantity between this 2 dates comes from base table like

select segment1,quantity
from po_lines_all pll, mtl_system_items mts
where pll.ITEM_ID=mts.INVENTORY_ITEM_ID
and creation_date between :FROM_DATE and :TO_DATE

and payment_terms should enter manually

3)2nd block contains summary button when i click on it, it save segment1, quantity, payment_terms and open new window which contain segment1 ,qty, payment_terms and when i click on summary button data comes from custom table which group clause means

suppose

item qty terms
a 2 2days
a 3 2days
b 3 3days

then on third form i shows like this
a 5 2days
b 3 3days

i done all this things but problem is that

suppose once data between 21-aug-2010 and 24-aug-2010 comes on second form , i enter payment_terms and save it. sumaary form also run properly but if another user enter date between 22-aug-2010 and 30-aug-2010 then it will shows data between 21-aug-2010 to 24-aug-2010 from custom table i.e with payment terms as earlier it save and from 25-aug-2010 to 30-aug-2010 it shows data from base table

like

item qty terms date
a 2 2days 21aug
a 3 2days 22aug
b 3 3days 24aug
b 4 NULL(ENTER MANUALLY) 26aug
c 5 NULL 27aug