Are you sure? Need an explanation!
Yes, I am. There is no need to do it more often.
Service manuals are written to make you pay for things that are simply not neccessary.
How often were valves adjusted in old cars that had similar valves like our scoots?
If you do not trust me, adjust them and check them in 1000, 2000, 5000 kms and decide for yourself.
On my gf`s A125 they were first time adjusted I think around 16.000 kms and they were just a bit off.
My P250S has 14.000 kms and valves are not yet checked and there is no need.
You will find online people who change oil every 300 kms and adjust valves every 1000 kms, but that is not because it is needed, it is because they have some spare time on their hands. I have seen even on this forum people who spend an hour checking scoot every day before going to ride, and I am not talking about your regular pre-ride inspection, but some real OCD stuff.
So, think for yourself, do some research online and decide what works best for you.