The in game statistics gives you a lot of useful information about your mining rates, but you can only compare previous to current changes under stable shard speeds. Shard speed changes can mislead you unless you make an estimation to account for it. What I believe other players and myself end up doing is searching for another ai within the game to use as a reference (who hopefully also hasn't made changes).
But I wouldn't have to do that if the in game measurements were tick based instead of time based. If this is too much of a jump for newer players to grasp I would settle for it being an advanced check box in options.
This would also help compare room performances across shards.
(edit added title)