exhalt:
This is and always has been called Marketing jargon. It is just a matter of semantics. Nothing to get hung up.

In the US when some folks talk about braking capability the say the lift truck cane stop on a dime, in GB they say it can stop on a six pence. I don't know which one is larger but it doesn't cause it ain't possible

For decades most every manufacturer of ICE lift trucks (in the US) called their OEM air cleaners Heavy Duty. In reality there is nothing really Heavy Duty about them when it comes to filtering capability. Most air cleaner element as I recall are rated on air filtration efficiency at a give vacuum std. Donaldson A/C were rated something like 99.8% to 99.9% fro a given micron size of dirt particles. The only difference among most filters is the number of sq. in. or (cm) of the filtering media and the micron size filtering capability. The more "paper" the longer the service life. The cheapo after market filters needed to be replaced more frequently and engine work too as typical the larger dirt particles are allowed to pass through.