How to Automatically Change a Cell in Google Sheets Based on Multiple Variables -

i working on creating schedule in google sheets , have 1 last task cannot figure out. here example of accomplish.

for lines 8-12 (which employees 1-5) need have script looks every cell contains either or a-10. if these or a-10 shifts fall on 1-15 (days of month in row 5...pictured below) should changed aa or aa-10. if fall on 16th-end of month should ap or ap-10. same case r , shifts.

here screen shot of google sheet example gave above:

any appreciated! thanks!

here script changes. changes rows 8 - 12 , assumes dates in row 5.

function changevalues() {   var ss = spreadsheetapp.getactive();   var sheet = ss.getactivesheet();   var range = sheet.getrange("8:12");   var dates = sheet.getrange("5:5").getvalues();   var values = range.getvalues();   for(var row = 0; row < values.length; row++) {     for(var column = 1; column < values[row].length; column++) {       var day = number(dates[0][column].replace(/[^0-9]/g, ""));       var value = values[row][column];       if(day >= 1 && day <= 15) {         if(value === "a") value = "aa";         else if(value === "a-10") value = "aa-10";       } else if(day > 15) {         if(value === "a") value = "ap";         else if(value === "a-10") value = "ap-10";       }       values[row][column] = value;     }   }   range.setvalues(values); }