The reason they don't want the vac advance used is because it is a generic tune and will need specific dialing in to match your motor and car-truck . Plus they have no control over what fuel you will fill the tank with.
Its up to you to dial it in. May want to replace with a fully tunable vac adv.
Some allow up to 20+deg at high vacuum basicly for EGR equiped engines.
Too much for a non egr engine... limit it to a max of 12-15deg at highest vacuum.
The rate has to be found by drive testing.
The mechanical cent advance set up is pretty generic too. Can also benefit from fine tuning too.