If your load order is like above, I think you can just use load order as sort order.
Another option is to create dual values for each field value, with a text and a numerical representation. Use the numerical representation for sort order.
LOAD dual(FIELD,recno()) as FIELD
Until 3 Months
Until 6 Months
One more option would be , simply load your information in line table with the order you want to sort and you may also drop the line table at the end of the script. You can now sort the field in multi box using Load order.i.e Right Clik on MultiBox--> Properties-->Sort Tab-->Sort By "Load Order"
Hope this helps you.