No, firmware version numbers are burned into the firmware. A few models have firmware that can run in different modes, e.g. a 48 V and a 24 V model could use the same firmware, and change "identities" by reading a voltage on a pin at start-up. But I don't believe that the 74.XX and 72.XX series ever merged like this.
The 72.20 firmware, and all 72.XX since about 2016 (there is version number overlap ) are for PF1 64 V.
The 74.40 firmware, and all 74.XX versions, are for PF1 58.4 V.
So the difference between these two is the maximum battery voltage, and this is related to a difference in the hardware: the transformer turns ratio is different. There are constants in the firmware directly related to the transformer turns ratio, so it's important to get the right firmware version.
Confirmation bias perhaps? I can't say. Unfortunately, some models don't reveal their "64-voltness" by something as obvious as saying so on the big sticker on the side with other important information (such as the colour of the case, sheesh). Some (most?) have "64" near the end of the model number, if they are a 64-V model. You could find out for sure by checking the waveform of the output at low battery voltages; see this post. Or maybe find a photo on the web of the 64 V version your model, and finding that it has "64" in the model number (where yours doesn't). It's sad that they indicate the 58.4 V models (which suit most 48 V nominal batteries much better) by the absence of a number, and that absence isn't always proof that you have a 58.4 V model.Or I was blind when I read it first time.
Yes, if you're sure that your machine is a 58.4 V model (e.g. perhaps you recall that you could never get any battery voltage settings past that value, or you find no clipping with a 47 V battery), then you need to reflash to a 74.XX firmware, and yes 74.40e is the fully patched firmware (feature equivalent to 72.20e) for this series.Anyway, is patched fw for this case 74.40e? Shall I use it instead old 74.10?