The validity range of IMRPhenomP is at 0.25, passing this value would result in unreliable results due to the limitations associated with it.
Further calibration to allow for estimation of greater mass ratios within this specific waveform has yet to be implemented.
Start new runs on IMRPhenomD (calibrated mass ratio 1:18) and determine the lower bound on the mass ratio for a set range of sources as before.
Feel free to shoot me an email if you have any questions! Cbustos(at)neiu.edu or Cbustos93(at)yahoo.com ~Cesar