How to setvalues() in the row of a column which is in the same row as a cell in another column with google apps script

I have the following script which works great, for a product code in column P of the BLOCK ORDERS sheet, ss1, it extracts the price from either the quotation worksheets ss2 if a sheet name matches the name of a particular customer, or if not then the price is taken from products sheet ss3. The price is input into column Z of the BLOCK ORDERS sheet. The problem I have is how to get the script to put the price in the same row as that of the product code?

function updateQuotationPrice() { 
  
  var ss1 = SpreadsheetApp.openById("1VlLbwBtYyOQBRz-8JHRn_jVhaAC7Tl68OXSltoQwaBU"); //BLOCKS UPDATE 
  var ss2 = SpreadsheetApp.openById("10tb0zE_8i849T-hL6mU-Pw_4V-aMzNZJGNOFYG1F3qk"); //Quotation
  var ss3 = SpreadsheetApp.openById("1pt7YnN9fmoD4PE0o9oVPezK8Qz6ZmabyJbWXfdzFeMU"); //PRODUCTS
 
 //Extract data from User Update
  var lr1 = ss1.getSheetByName("BLOCK ORDERS").getLastRow();
  var data1 = ss1.getSheetByName("BLOCK ORDERS").getRange(2, 6, lr1, 61).getValues();

  //Extract data from Quotation Spreadsheet
  var sheetNames2 = [];
  ss2.getSheets().forEach(x => sheetNames2.push(x.getName()));

  //Process data 1
  var output = [];
  data1.forEach((x,i) => {
    var zoneSurcharge = x[58];
    
    if (sheetNames2.includes(x[0]) && ss2.getSheetByName(x[0]).getDataRange().getValues().filter(y => y.includes(x[10])).length > 0 ) { 
      if (x[9] == "EURO" && x[10] != "") {
        output.push([ss2.getSheetByName(x[0]).getDataRange().getValues().filter(y => y.includes(x[10]))[0][3]+zoneSurcharge]);
      }
      else if (x[9] == "STERLING" && x[10] != "") {
        output.push([ss2.getSheetByName(x[0]).getDataRange().getValues().filter(y => y.includes(x[10]))[0][2]+zoneSurcharge]);
      }
    }
    else  
      if (x[9] == "EURO"  && x[10] != "" ) {surcharges = zoneSurcharge 
        output.push([ss3.getSheetByName("PRODUCTS").getDataRange().getValues().filter(y => y.includes(x[10]))[0][3]+zoneSurcharge]) ;
      }
      else 
      if (x[9] == "STERLING"  && x[10] != "") {surcharges = zoneSurcharge 
        output.push([ss3.getSheetByName("PRODUCTS").getDataRange().getValues().filter(y => y.includes(x[10]))[0][2]+zoneSurcharge]); 
      }   
  });
  console.log(output);
 //Output 
 ss1.getSheetByName("BLOCK ORDERS").getRange(2, 26, output.length, output[0].length).setValues(output); 
   }

The output range ss1.getSheetByName("BLOCK ORDERS").getRange(2, 26, output.length, output[0].length).setValues(output); starts at row 2. I require the output to correspond with the same row which contains the product code. Sometimes the product code could be in row 2 or row 3 ,or row 4 etc.
The BLOCK ORDERS sheets can be viewed at
https://docs.google.com/spreadsheets/d/1VlLbwBtYyOQBRz-8JHRn_jVhaAC7Tl68OXSltoQwaBU/edit?usp=sharing
The QUOTATIONS sheets can be viewed at
https://docs.google.com/spreadsheets/d/10tb0zE_8i849T-hL6mU-Pw_4V-aMzNZJGNOFYG1F3qk/edit?usp=sharing
The PRODUCTS sheets can be viewed at
https://docs.google.com/spreadsheets/d/1pt7YnN9fmoD4PE0o9oVPezK8Qz6ZmabyJbWXfdzFeMU/edit?usp=sharing
Thank you for any help with this

I don't know if there are any edge cases that you need to take into account, but the way your current script works, the output prices will always be in the same order as your products in column P. So all you need to do is to fill the output array with blank strings when you also find a blank product. So your loop would look like this:

  var output = [];
  data1.forEach((x, i) => {
    var zoneSurcharge = x[58];
    if (x[10] == "") {
      output.push([""])
    } else {
      if (sheetNames2.includes(x[0]) && ss2.getSheetByName(x[0]).getDataRange().getValues().filter(y => y.includes(x[10])).length > 0) {
        if (x[9] == "EURO" && x[10] != "") {
          output.push([ss2.getSheetByName(x[0]).getDataRange().getValues().filter(y => y.includes(x[10]))[0][3] + zoneSurcharge]);
        }
        else if (x[9] == "STERLING" && x[10] != "") {
          output.push([ss2.getSheetByName(x[0]).getDataRange().getValues().filter(y => y.includes(x[10]))[0][2] + zoneSurcharge]);
        }
      }
      else
        if (x[9] == "EURO" && x[10] != "") {
          surcharges = zoneSurcharge
          output.push([ss3.getSheetByName("PRODUCTS").getDataRange().getValues().filter(y => y.includes(x[10]))[0][3] + zoneSurcharge]);
        }
        else
          if (x[9] == "STERLING" && x[10] != "") {
            surcharges = zoneSurcharge
            output.push([ss3.getSheetByName("PRODUCTS").getDataRange().getValues().filter(y => y.includes(x[10]))[0][2] + zoneSurcharge]);
          }
    }
  });

As you can see, I just encased everything in another if. So for a product input like ["B94", "", "B94", "C3520"] your output will look like [[ '77' ],[ '' ],[ 71 ],[ '103' ]]. The products will match with their prices. You can also add to the condition any other columns that you expect could be blank like currency, or to validate for missing product codes, but this will depend on how your sheet works. The general idea is that you just want to fill the output with blank rows whenever you cannot retrieve a price so it will match the input.

The hard way would probably be something like keeping track of the index rows in the forEach to create a RangeList with only the valid rows and then set their values. This seems overkill for your use case, though.