Hi Asterix, welcome to the forum, you know we are here for what you need.
In the first place I have read your post about what happened to you with rmotos, and tell you that you have done well to report them and even better to publish this so that people realize that they are not alone in these cases.
Regarding your question of the double optics on motorcycles, I tell you, in cars the double optics is also being implemented in the headlights because it has better light performance, that is, if you make a lighthouse for short, with a lamp Ex, H-7 and another for long lamp with H-1 lamp, you take better advantage of the luminosity that each bulb provides because the parable design adapts perféctively.
When you mount an H-4 combined lamp lighthouse, you limit the road optics for the benefit of the crossing, I explain myself:
Normally the light that is for a longer time is that of crossing, so that the parable is designed for this beam of light, sacrificing some dimensions in the road, so that although you have 60W in long, they do not illuminate the same as the 55W of the lamp H-1 with the Specific Lamp.
Double optics in cars, do not turn off when you turn on the road, (H-7 + H-1) so that light beams are supplemented.
On motorcycles, this is not usually done for the issue of current consumption, because the magnetic steering wheel is not able to replace the 110W that consumes the lighthouse in lengths and feed the injection and ignition without causing significant tension falls.
I hope I have clarified the doubt (it looks like a will).
All the best.