It's definately mostly type specific and thus how tolerant the aircraft is to a change in load and C of G. The aircraft I fly is 2000Kgs. nominally, but you have to use your loaf! If someone just loaded 2 tonnes in the No1 or No 5 hold I think I would do a new load sheet regardless or at the very least a new drop line. You should also use a little more caution when using standard weights and compartmented load or container data. Sometimes this data can be quite away out. So cover your back, if there is a niggling of doubt do a new load sheet.