Google-sheets – How to return all results associated with an input cell in Google Sheets

Assuming the actual finishing date is in Column F and the sheet is called Sheet1, paste the code below inside your spreadsheet under Tools >> Script editor, then hit Save.

/***
* Color Code+ 
* Conditional formatting with cell referencing for Google Spreadsheets
* Support: scripts@bryanp.com
**/

function onEdit() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var s = ss.getSheetByName('Sheet1');
var values1Rule1 = s.getRange('E1:E').getValues();
var values2Rule1 = s.getRange('F1:F').getValues();
var range3Rule1 = s.getRange('E1:E');
var color1 = 'red';

for (var row in values1Rule1) {
for (var col in values1Rule1[row]) {
if (values1Rule1[row][col] == values2Rule1[row][col]) s.getRange(s.getRange('E1').offset(row, col, 1, 1).getA1Notation()).setBackgroundColor(color1);
else s.getRange(s.getRange('E1').offset(row, col, 1, 1).getA1Notation()).setBackgroundColor('white'); }}
};

I used this script generator to make creating the code easier. You can adapt it to your needs.

As mentioned in the comments, I would probably recommend to rewrite your logic from using lots of formulas, into using one/a few Google Apps Scripts.

See this example spreadsheet. It includes a Google Apps Script function that returns an array of 6 random numbers:

function giveMe6RandomNumbers() {
  return [Math.random(), Math.random(), Math.random(), Math.random(), Math.random(), Math.random()];
}

I can then call this function from any cell with =giveMe6RandomNumbers(), and it will fill that cell, and the 5 next cells, with random numbers.

As long as we are talking about just a few formulas, the difference in performance will be small, perhaps even opposite. But in my experience, a huge number of formulas will give bad performance, and moving the logic into a script function performs better.