Its an educated guess. here is why I think it is pure luck on the part of DDM tuning, first all DDM kits come from china & are Chinese made, that is a fact it ships from china.
when HID came out a few years ago you could find different kinds of H4 bixenon Hi/ low bulbs they all use a magnet mechanism to pull back the bulb when current to the magnet is on, cut off the current & the bulb telescope to its original position, when the bulb retracts this is the high beam & when it telescopes this is the low beam, this is achieved in combination with a fixed chrome shield that has an opening in its lower section.
The Chinese supplier of DDM tuning has bulbs that are a few mm shorter at the back than the common H4 bixenon bulbs from china, this does not jam against the headlight housing, DDM did not specifically want shorter bulbs because in most cases the longer ones fit & function great, on the vmax the standard long back bulb require cutting the back of the headlight plastic housing to fit properly and to be able to use the adjusting screws to aim the headlight, if you don't cut the housing you still can assemble the headlight with some pushing but that makes the adjusting screws useless since the back of the bulb is jammed against the housing. in some cases the bike owner finds that the aim of the headlight need no adjustment even with the bulb jammed to the back of the headlight plastic housing, this is usually because the bike hight was altered by lowering the forks or shocks or both.
the controller unit with the HID kit turns on & off the current to the magnet to switch between hi & low beams, the bulb itself remains on.
See photos