Finding Smallest Value In Range Close To Specified Calculated Point

Lets pretend that I have a boat load of automatically generated values from a different program.

There's a specific equillibrium point to a certain measurement, but this measurement involves a lot of fluctuation. To get a near accurate result, I must find the maximum value in an entire graph on the Y Axis value(Column B). Ofcourse, this is easily done using the =MAX value

Exactly 450 seconds (X Axis value(Column A)) positively and negatively from this point, something like this happens.

Problems:

A.) I must find the highest points 450 seconds negatively ( X ) to the max of the entire graph.

B.) I must find the lowest point closest to the two points we uncovered, both on the positive ( X -->) side.

C.) The fluctuation of every spike can last to about ±30 measured points in the graph. (±20 seconds) Thus, the maximum point surrounding the +/- 450 seconds (±693 x values) needs to be accurately predicted as being around 450 seconds, not 10 seconds more or less.

D.) The measurement is known to something glitch out and suddenly get a spike somewhere along the road, which will then quickly fall back down, which is a false maximum level. How can I prevent excel from taking this as the maximal point?

Remember, this needs to be fully automated into a macro later on, ergo, I cannot manually add the formulas to all the (650 different) sheets.

I have 25 days before the project gets cancelled if this doesn't make it.