David,
If your measured OG is 1.052, you must have achieved plenty of conversion when heating from 122 to 180. Personally, I would count that as done and proceed.
Had the OG been a little lower, I would have proceeded with a smaller beer. Had the OG been much lower, adding a separate source of enzymes may have been required to salvaged the batch.
On a related note, your acid rest at 122 isn't likely necessary unless you are brewing a style with large amounts of wheat (think Hefeweizen). And even then, maybe unnecessary. Malts of today are different than historical, and do not required complicated mash schedules of the past. Almost all my mashes are performed at a single temperature, plus mashout.