Modern Vespa

I got an oil change 1st service at the local dealer
After I paid the service writer handed me a jug of oil, I didn't pay any attention, at the time
I never saw 10-60 weight oil before

so they charged you for a gl of oil and only used 1.5 qts at the most and gave you the rest. now you can go back and have them drain that 10-60 out and put in the proper weight oil.

my guzzi calls for 10-60 but the mp3 is 5-40.

Better choice for a motor with a reputation for using oil...
The oil doesn't fall out of the oil pump after sitting over night as often

Good brand, wrong oil weight, mechanic needs to be fired or sent off to work on equipment more on his level.

This Motul oil linked below would have been the correct choice.

https://www.motul.com/be/en/products/300v-4t-factory-line-5w40

In your owners manual - is 10/60 in the acceptable range of weights for your current temperatures ?
There are usually an acceptable range of oils.
O.S.