SELECT "PLAN_ITEM_ID",
       SUM("SECONDS_PER_DAY" * (
         SELECT count(1)
         from generate_series("START_TIME", "END_TIME" - interval '1 day', '1 day') as days
         where extract(isodow from days) < 6
       ) - (SELECT count(1)
			FROM "AO_013613_HD_SCHEME_DAY" JOIN (
				SELECT  generate_series("START_TIME", "END_TIME" , '1 day') as days
				FROM "AO_2D3BEA_PLAN_ALLOCATION"
				WHERE "PLAN_ITEM_ID" = 374447
				)U
			ON "AO_013613_HD_SCHEME_DAY"."DATE" = U.days))
FROM "AO_2D3BEA_PLAN_ALLOCATION"
WHERE "PLAN_ITEM_ID" = 374344
group by "PLAN_ITEM_ID";