The "gibberish" is the only way to explain what MED/hr means.
Model 5.0: browning rays (melanin oxidation tanning photons)
Model 6.0: pinking rays (melanin stimulation photons)
Model 7.0: reddening rays (burning photons)
Is that simple enuf? The lamps provide a "mix" of all three types (bandwidths).
Some people only care about the "burning rays" and their relationship to Te time to 4 MEDs. 240 / MED.hr = Te in minutes. Also good for acrylic transmission checks. But the other models are needed if people care about "tanning" rays and UVB amount or percent.
Read the IST article:
Island Sun Times