Hello,
One limitation to using parametric simulations is that it is harder to investigate the hourly (or subhourly) results. You can generate tables of the data, but it is unwieldy to investigate.
My recommendation in your case would be to simulate the parametric case that produces the low LCOE results separately so that you can use the Data tables, time series and other tabs on the Results page to investigate the results in detail. That investigation should help answer your question.
The other advantage of running an individual simulation is that you can see the simulation notices and warnings that are not available with the parametric simulation results. Those messages may provide some insight into your question. To see the messages after you run a simulation, click the Notices tab on the Results page.
Best regards,
Paul.