Harold's numbers aren't unstable. He's bouncing! Many cats see lower numbers at night. Some cats are truly nocturnal and may be more active at night which may contribute to their BG numbers being a bit lower. However, you're beginning to see some of the same numbers during the AM cycle. Since we generally don't know how long our cats have been diabetic, when they start to see lower numbers, their liver and pancreas overreact because they think the low numbers, even if they are higher than normal range numbers, are dangerous. Their system has gotten used to the higher numbers. As a result of the lower numbers, the liver and pancreas release a stored form of glucose along with counterregulatory hormones. This causes the numbers to spike back upward. So you see the blues and some hint of green at night and by the AM cycle, numbers bounce back up into the pinks.
Harold looks like he's responding well to Prozinc. I would have gotten some additional tests after those mid-cycle green numbers, though. The 74 indicated the need for a dose reduction. I'm tagging
@JanetNJ so she can have a look, as well.
I'm also going to ask
@Bandit's Mom to take a look at your spreadsheet. The row numbers on the World Template and the US tab are not lining up. You have values for today on the US tab in row 102 but there's noting on today's date (row 104) on the World tab.
It will also help if you can manually enter the values that don't translate from the World tab to the US tab.