The study said in summary when describing the statistics:
There doesn't seem to be a connection between added pressure and occurrences of central events as shown in the data. Notice that the OP had zero centrals at a pressure of 18/14 cmH2O and all the events were hypopneas for an AHI of 11.6, much better than he is now getting. At a fixed pressure of 11 cmH2O as mentioned in the summary above, the OP had zero centrals, and an AHI of 10.0.RESPIRATORY PROFILE. The patient was presented with the incremental application CPAP. As anticipated, he required very high pressure 20/14cm, significantly higher than what the auto Pap was delivering. For comfort, he was switched to bi-level positive airway pressure to accommodate the higher pressure. He also did relatively well on 11 cm, but the higher pressure of 20 cm was superior. Relevant pressure with duration, AHI, RDI, mean oxygen saturation is as follows:
This would suggest that either there is a real (but minor) central issue that is somewhat exacerbated by the higher pressure or, because of the amount of time awake during each pressure change, the centrals occurred close to the sleep-awake transitions. Notice that at the 11 cmH2O pressure, the OP did not wake up during the period. At the pressure of 20/14 cmH2O, the OP woke up for a total of 40.5 minutes out of total duration of 170.5 minutes (about 23.7% of the time.) That's a lot of sleep fragmentation.
With the centrals averaging 30 seconds, it may be better to consider a lower IPAP pressure and a narrower range such as 18/14 cmH2O.
As always, get on board with your doctor about any changes to the pressure. You report feeling somewhat better and the centrals don't seem to be doing anything really harmful since, in the titration study, the average SpO2 level stayed above 94% more than 99% of the time. He doesn't report any SpO2 data at home. Perhaps getting a recording pulse oximeter would be helpful in collecting more data, evaluating the effect of the centrals, and contributing to his feeling that this is OK right now but could be better with a little tweaking.