insert into #price (PriceID, Product, [Value])
select 1, 1, 100.20
union all
select 2, 1, 110.20
union all
select 3, 1, 20000.20
union all
select 4, 2, 10.00
union all
select 5, 2, 20.00
union all
select 6, 2, 10000.20
union all
select 7, 1, 0.20

;with maxPrice as (
	select top 1 with ties * from #price order by row_number()over(partition by product order by [Value] desc)),
avgPrice as (
	select Product, avg([Value]) avgPrice, max([Value]) as maxPrice from #price where PriceID not in (select PriceID from maxPrice) group by Product)
	
update a
set a.Value=b.avgPrice  
from maxPrice a inner join avgPrice b on a.Product=b.Product 
where a.Value >= 11.0 * b.maxPrice 	

;with minPrice as (
	select top 1 with ties * from #price order by row_number()over(partition by product order by [Value])),
avgPrice as (
	select Product, avg([Value]) avgPrice, min([Value]) as minPrice from #price where PriceID not in (select PriceID from minPrice) group by Product)
	
update a
set a.Value=b.avgPrice  
from minPrice a inner join avgPrice b on a.Product=b.Product 
where a.Value <=  b.minPrice / 11.0

;with cte as (
	select 
		*
		,mPrice	=PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY [Value]) over(partition by Product) 
	from #price),
cte1 as	(
	select 
		*
	from cte
	where Value >= mPrice * 11.0 or Value <= mPrice / 11.0),
cte2 as (
	select 
		Product
		,aPrice	=avg(Value)
	from cte
	where not(Value >= mPrice * 11.0 or Value <= mPrice / 11.0)
	group by Product)

update a
set a.Value = b.aPrice
from cte1 a inner join cte2 b on a.Product=b.Product