the reason for the +2 is that often when it is significantly lower than the pre-shot test, it can indicate an active cycle where you might want to set
an alarm and check again for lower numbers. Most kitties go lower at night ( inconvenient, I know) and you did have a green not that far back.
If he were still doing that every other day, you would hold the dose where if he is not seeing any more green, it is time to increase.
I would be inclined to go up to 3.25 now as you haven't seen a green in days.