(Adds table) LONDON, July 1 (Reuters) - Saudi Aramco cut its August official selling price (OSP) for Arab Light crude oil to Asia by 20 cents a barrel to the Oman/Dubai average plus $2.05 a barrel, it said on Tuesday. Saudi Aramco kept the Arab Light OSP to the United States unchanged at the Argus Sour crude Index (ASCI) plus $3.65 a barrel. The Arab Light OSP to **rthwest Europe fell $1.65 a barrel to the Brent weighted average (BWAVE) minus $4.35 a barrel. The tables below show the full FOB prices for August in U.S. dollars. ...