Help with formula

I have data readings on a worksheet in cells B3:AF12 (10 rows deep x 31
columns wide).
I also have a date in cells A3:A12. One date for each row of data that was
taken.

I have the following formulas set up in order to forecast, when a designated
Minimum value is to be reached.

The below is the formula's i am using to forecast when the value set in A15
will be reached for each individual column of data.
The result is displayed as a date, calculated from the list of dats in
Column A..
B16=FORECAST(A15,A3:A12,B3:B12) ..... ..AF16=FORECAST(A15,A3:A12,AF3:AF12)

A16 - basically formulates the lowest(min) reading across the data in row
16, and displays the date when this forecast data will reach the set value
in A15.
A16=IFERROR(MIN(B16:AF16),"")

However, rather than just relying on the Single most Lowest reading to
Forecast, i want to set a percentage of data values to set the Forecast
data.

eg. Instead of the lowest reading being forecast by a date, i want say the
date forecast to be when 10% of the reading will reach that amount.


How would i go about changing the single MIN value to a set Percentage(say
10%) instead?

Corey....