OK...if you're always getting Pre-shots that are too low to shoot, that usually means the dose is too high
When you first start, we say there's a "no shot" limit of 200, but that quickly falls to 150...but it also doesn't mean you don't shoot! (makes sense, right?...LOL)
What we mean is that when you first start getting lower PS tests, you should "stall", DON'T feed and post for help. Make the subject line clear like "Stalling, need help!!" so the people that scan the forums notice. As you get more and more data, that "no shot" limit drops too! As you saw on China's spreadsheet, I'll shoot anything above 50, but that's because I've got the data and the experience to know it's safe to do it. As you gain more experience and data on Gryff, you'll gradually need to learn to shoot lower and lower numbers too.
I realize when you see your cat drop from 200 to 100 that it just makes sense that if you shoot at 100, they're going to drop to zero, but it just doesn't work that way! Shooting low numbers can give you some of the most gentle cycles, where they may only drift up or down 15-20 points over the entire cycle.
We also have an unwritten rule around here that the first few times someone shoots a lower number, if we agree to help them, we don't leave them until we all know it's totally safe to stop watching .....If one of us does have to leave, we'll find someone else to take over if we have to!
One more thing (still trying to figure out your spreadsheet)....We generally TEST/FEED/SHOOT....all within about 5-10 minutes....you test to make sure they're high enough to shoot, feed to make sure they're eating "normally" and then shoot. With China, I test at 6am, put her food in the bowl to make sure she's eating and then shoot (usually while she's still eating) so the whole thing doesn't take me 5 minutes and then repeat again at 6PM
Older types of insulin, it was really important to feed first and then give the shot 30 min or so later, but with Lantus, that's not necessary.