Assuming Daylite is returning an AppleScript "date" object and you don't need the actual date later in your macro, a quick way to return values based on whether "formCreateDate" is more than 60 days before the start of "today" is:
if ((date (date string of (get current date))) - formCreateDate) / days > 60 then
return 1
else
return 0
end if
...with the "Execute AppleScript" action set to "save results to variable" and "Save to variable" pointing at your "form Create Date" (you might want to rename that to more obviously reflect its purpose, eg "isMoreThan60DaysAgo") -- you don't need the last "tell block in your AppleScript.
If you want to use the current time of "today" it's even simpler:
if (get (current date) - theDate) / days > 60 then
return 1
else
return 0
end if
You can then use "if 'form Create Date' is 1" for your ">60 days old" test.
If you do want to use the returned date in KM -- maybe as part of a file name -- you might be better off returning the date as a text string that you can then manipulate in KM.