The FAA action, while supposedly not directly related Lion Air but more to Xtra's problems with working on parts they were not authorized to work on because they hadn't demonstrated that had everything in place, is obviously politically related to the event because the crash put the spotlight on Xtra and the FAA had to do something once having lifted that particular rock.
So from a strictly legal standpoint, Lion Air's maintenance actions don't help Xtra and what will happen is Xtra will have to make reforms and then go back to the FAA to try to get their repair cert reinstated independently of any Lion Air actions.
Normally what happens is a part goes to a repair facility, and the repair shop puts it though an Acceptance Test Procedure (ATP) as per the manufacturer's Component Maintenance Manual (CMM). There is usually some kind of test rig that has to be made (instructions for making it in the CMM), that runs the specified functional tests on both ingoing and outgoing parts.
So the part goes in, and gets an incoming ATP. If it passes the incoming ATP, it's considered serviceable and gets tagged NFF (No Fault Found) and sent back to the airline as serviceable. If it fails ATP, it gets broken down and repaired as required. It then gets an outgoing ATP (the same test normally) to validate function before it is tagged repaired/serviceable.
I can't really tell from the article if the mis-calibration was inherent to the vane as received or was something screwed up when the airline installed it. Notwithstanding the likelihood that Xtra was turning parts around that they don't appear to be approved to repair, it's not uncommon for parts to come back to an airline NFF, or repaired, and still fail when it's installed on the plane.
So either Xtra had the proper manual, test rig, parts and tools, training etc. for fixing these vanes or they didn't. The FAA's action makes it sound like they didn't and were maybe just receiving units and doing some other test they made up themselves, or maybe just smiled at it and sent it back out. Hard to say.
In any case, receiving a part back with a serviceable tag is no ironclad guarantee that it will work in service, and "bad from spares stock" happens from time to time. No system is perfect. The business depends to some degree on the redundancy of having two and three of everything to cater to random failures no matter the background causes, except in this instance Boeing decided to let that single-point-of-failure spot in the system architecture get through cert, and here we are.