Some computers may experience errors or conflicts with the 64-bit version of the WTM, either due to a windows or VBA version or build date, and on some older machines. For those users, the “WTM 2013 off the shelf – no macros” version is available. The calculations in this version are exactly the same as in the 64-bit option, but the user is not able to use check boxes to reveal only portions of each sheet.