In answer to your question(s) about previous audits, there have not been any until now.
The ballots were "canvassed" in November, which is standard procedure. Canvassing is recounting a small sample of the ballots, and there is supposed to be further examination if the recount shows an error rate of a fraction of a percent. The samples in Maricopa County showed greater than a 1% error rate, and that error counted Trump votes as a Biteme vote on Election day. The error rate in the canvas could have easily been enough to swing the close election.
And this was a half-assed machine canvas,
not hand count. Worse, even though it showed an unacceptable error rate, there was no further analysis done because the R Governor and AG, along with the Rat Secretary of State nixed it.
What is going on right now is a 100% audit, which is much more than a simple recount. Ballots are being UV scanned for the proper watermarks. The Dominion counting machines (all 400 or so of them) are being checked to see if they were tampered with. And yes, it's a hand count.
This Audit was made necessary by the Democrats' and RINOs' refusal to follow procedure and do deeper recounts when the Canvassing failed (and make no mistake, it failed! That's the "previous audit" we have problems with).