[Amps] Bird 437-3 element for bird 43？

[Yueh Hsu]

Just view the website https://nm3e.com/HElements.htm, it mentioned that
437-3 element not for bird 43 wattmeter, but I knew element  437-3 match
with line section 4230-053 and 30uA/1400ohm meter,  Bird43's meter is
30uA/1400ohm , and line section 4230-053 often match with bird 43 elements
too.
    Question:Why 437-3 element can not use in bird 43?just it can not
handle 10kW(I knew,bird 43's element's power only 5000W(5000H）？
  Hsu