I seem to remember that I saw their is a default advance scouting and college/high school ratings. Is this correct and if so when you take all scouting to zero does the default kick in ?

I've never heard of default scouting ratings. Doesn't necessarily mean there is none but if after 87 seasons over 10+ years I have not heard of them, I doubt there are any. One still sees ratings with a zero scouting budget (if your scouts actually find any prospects) but those ratings will be ridiculously far off from what the prospect actually will end up being.

There is no default. Your scouting is based entirely on how much money you put into it. That's why projections don't exist until after budgets are finalized.