DAYS360 function
    DAYS360(Date1,
    Date2, Method?) DAYS360(Date1;
    Date2; Method?)
  
  Date1
        Number or { Number }
      
      The first date, as a sequential serial number.
Date2
        Number or { Number }
      
      The second date, as a sequential serial number.
Method
        Logical or { Logical } (optional)
      
      FALSE to use the US NASD method and TRUE to use a European method. If omitted, FALSE is assumed.
Returns
        Number or { Number }
      
      The number of days between two dates, assuming a year with 360 days.
Returns the number of days between two dates. Unlike the DAYS function, this function is based on a year with 360 days (divided into twelve months, each containing 30 days).