I would be systematic about it. Hold the dose for 4 - 6 cycles, (2-3 days), whatever works best for you in that range, and if at that point nadirs are above 50 and PSs are above 150, raise by 0.2, then keep repeating that until you get the numbers. And lower of course immediately if you see numbers under that.
If this dose is 100% obviously too low I would say you don't need to hold it as long (but I would hold any increases for at least 4 cycles). The thing is you can't judge just from a high PS. Tonight's PS is surprisingly good, and you got over a 50% drop by +3 on one cycle at 1.4, so I'd be tempted to just hold this for 2 days and then raise if the numbers aren't good.
The exception would be if you see an increase in his symptoms or if he acts like he is feeling worse. Those are signs the dose is too low, and I would go ahead and raise if you see that, assuming the numbers aren't great.