@hawk & mouse, yes both of you have your point.
As a private person who is not responsible against any warranty claims you can use any oil available and fill your KYMCOs gear with.
Even simple motor oil would do, as long NO other complications like a rough bearing, low oil level,
rough sprocket, excessive driving, etc. leads to a gear demage.
This is why, oil recomandations are set up by motor producers.
Not the hypoid oil itself will demage this oilseals, but this microscopical chemical changed surface of an axle.
During my professional life I saw (not on scooters) a lot of broken (sheared off) shanks up to adiameter of 150 mm, and to 80-90% wrong or no lubrication caused this fault.
Analyses are pretty simple on this items and oil types are very easy to distinguish.
To shorten the story, if you have to grant warranty
" Better safe than sorry".
Attached a pic from a KYMCO Dink 200i gear whose owner simply never checked gear oil.