I would belive thats just a Non-taxable to non-taxable. So no, if I understand your question correctly. You'd just be combining 2 Roths. For an actual Conversion I would also ust keep each conversion separate. Makes it easy for record keeping.
No waiting if you are 60 yo. Roth is great. I just converted too. Very easy to do it via Fidelity transfer within account from IRA to Roth. No need to call customer service. Pretty straightforward. If Nwbo is expected to rise soon, converting to Roth at much lower price is a good thing IMO.