Compare Cells above and below the current cell and check for greater value and sum

[arunramani]

In the below row Let say my current cell is 8. Now i need to check the above and below cell of current cell (8) on which is greater, and that greater value shud be added with current cell

Cell above current cell is greater so 6+8 =14
Now check the next above cell(7) with cell below current cell (5) and add the greater cell with 14 === 14+7 =21.. and so on likewise till some target value say =26. In a nut shell I want to calculate the value that are 70% of this range( from top cell to bottom cell of the below one. Pls help me to get some formula for this . Help is much appreciated
[TABLE="class: grid, width: 100"]
<tbody>[TR]
[TD]2[/TD]
[/TR]
[TR]
[TD]4[/TD]
[/TR]
[TR]
[TD]7[/TD]
[/TR]
[TR]
[TD]6[/TD]
[/TR]
[TR]
[TD]8[/TD]
[/TR]
[TR]
[TD]5[/TD]
[/TR]
[TR]
[TD]7[/TD]
[/TR]
[TR]
[TD]2[/TD]
[/TR]
[TR]
[TD]4[/TD]
[/TR]
[TR]
[TD]1[/TD]
[/TR]
</tbody>[/TABLE]