Unfortunately this is not the case. I've been at Tier 4 of this skill for ages. The reported scanned amount (for easy-to-monitor high tier ore nowhere near edges of the tile) can be both substantially under and substantially over the actual mined amount. Really, the only conclusion that I have is that the reported ore in the scan is just plain wrong, as I never get a consistent mined-ore/scanned-ore proportion. So we can't even tell if its +5% ore, or +1% ore or even -1% ore per tier.
Very unhappy with this skill in particular and the number consistency in the game in general.
Really, if NQ can't even be bothered to inform us what the talent actually does, the only way for us to know is to collect mined-ammount/reported-amount & skill level for a large-ish number of tiles (of non-edge ore), and see what we get. The data won't lie (and data recording like this has busted errors and lies in other games).