Our rated output is, by UL mandate, the RMS value of the peak voltage. Most people, because of core and coil transformers, think about the rating in terms of the peak to peak value of perfect sine waves. Our actual waveform is taller and skinnier than a perfect sine wave so our actual peak to peak value is even higher. What this means is:
1) Ignore the "Rated Output" unless you are comparing against another UL2161 rated switching power supply.
2) The "Equivalent Sign Volts" from the datasheet can be compared to the amount of a load that a core and coil transformer of that size could drive.
Thus instead of a 224, 226H, and 2610 we really have a 22(3.5), 22(6.4), and a 26(10) unit. The example is that if we compare against a competitors 5020 unit, our 226H can do much better at 6.4kV "Equivalent Sign Volts" and 25mA. Our 226H provides 1400V more strike voltage to power neon and 5mA more current to power argon.
"Okay", you say, "but the 224 is not a 4kV unit if all it can do is 3.5kV Equivalent Sign Volts". Well as I slipped quietly into the explanation above, Our actual waveform is taller and skinnier than a perfect sine wave so our actual peak to peak value is even higher. The 224 waveform is even taller and skinnier than its cousins the 226H and 2610. In fact, on an oscilloscope, the 224 will produce 4.3-4.5kVpk-pk ... which means it can provide just over 4kV of strike voltage for neon and up to 18mA for argon ... so we call it a 224.