Why are there separate electric (E) and magnetic (H) MPE limits at frequencies below 300 MHz?
Why Below about 300 MHz, wavelengths are long enough that you are often in the near field or in a complex environment where E and H are not simply related by the 377 ohm free-space impedance, so each field must be evaluated separately against its own MPE limit. All three statements are true: the body absorbs energy from both the electric and magnetic components, ground reflections and scattering make field strength vary from spot to spot, and the E field maximum and H field maximum can occur in different places. That is why MPE tables give separate V/m and A/m limits at lower frequencies instead of a single power density figure.
Watch out Picking just the near-field reflection point or just the body-absorption point is incomplete; each is a valid reason on its own, but the rule exists because of all of them together.
Below 300 MHz: E and H go their own ways, so measure both. Long wavelength means near field and reflections.