That last part isn't true. I don't know what the limits are, but the FQP Tool can be at least slightly lower than the Outdated Implant. I was able to use a QL 195 tool to turn a 201 Outdated Implant into a 201 final item.You will need the following items to make a Rebuilt NCU Wrist Implant:
Field Quantum Physics All-Purpose Tool
Outdated NCU Wrist Implant
... The Field Quantum Physics All-Purpose Tool can be purchased from general shops and must be at least the same QL of the Outdated NCU Wrist Implant.
In fact, the tools only go to 200, but the outdated and final parts can be as high as 300. Without some leeway, the higher QLs would be impossible to make. I couldn't do any testing into how far the QLs can diverge. I didn't do the actual combine, so I always got a "not enough skill" error.
Also, I noticed that the tool is not used up.