Cider pH tends to be around 3.5 pH, and no lower than 3. Your fermentation range is in the "moderate" category, if not close to cold for most cider yeasts. So, things seem positive for longer pectinase life.
Your dosing is at the limit of what I recommended in my first response. So, I'd just add the fruit and let it go. After a few days, you could chill a sample to < 38oF, and see if it's unacceptably hazy. If it is, try just one teaspoon for the whole batch, up to the full rate for the additional juice.
How many gallons of new fruit are you adding?