ACR v2 is never getting out of beta, it seems, so I'm not sure what to do at this point.
As far as your question goes, ACR doesn't have separate fertility settings for Plantsims (which is why adult Plantsims got such long lifespans; I wanted them shorter), so if you make your own aging mod using Maxis years for regular Sims and my years for Plantsims, you'll have to choose whether you want risky fertility for regular Sims (use the original controller) or Plantsims (use my controller).
Re: Am I doing this right?
As far as your question goes, ACR doesn't have separate fertility settings for Plantsims (which is why adult Plantsims got such long lifespans; I wanted them shorter), so if you make your own aging mod using Maxis years for regular Sims and my years for Plantsims, you'll have to choose whether you want risky fertility for regular Sims (use the original controller) or Plantsims (use my controller).