Just did some quick reading. Didn't find a LAG solution, but windowed functions are awesome for this.

In the OPs problem at hand, we need something other than ID to ensure sequence of rows. I'm creating one using ROW_NUMBER() but it really should be in the base table

; with cte as (select ID, row_number() over(Order by (select null)) as CalcID, SomeValue

from #sometable)

,cte2 as (SELECT ID, CalcID, SomeValue, sum(SomeValue) over(Order by CalcID ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) RunningTotal

from cte)

,cte3 as (SELECT ID, CalcID, SomeValue,RunningTotal, 175-RunningTotal as Remainder

from cte2)

select *, case when Remainder > 0 then 0

when ABS(Remainder) <= someValue then SomeValue + Remainder

else Somevalue

end as Newvalue

from cte3

Have a great weekend, everyone.