The new cycles high/low are probably a standard cycle the manufacturer has used for various other clients. There probably isn’t too much of a difference between the two cycles, honestly. They probably are very similar in regards to efficiency of removing air. At this point, you’re not trying to steam the parts (during pulse phase) you are trying to remove air, and both cycles are probably similar. DId you look at the number of pulses required also. That is another parameter which might be different based on the recommendation of the autoclave vendor, but maybe not.
Regarding validation, I hope you are going to re-validate the entire cycle (IQ, OQ, PQ, PV) - you might want to do an engineering study to show that all the air gets removed with the new parameters.