You're using a human meter right? When they hit about 50 on a human meter, we start to worry and steer. And honestly, it can depend. If you're hitting say...60 at the nadir point, I would say to just watch closely. If you're hitting 60 3 hours after the shot, we've clearly got a problem because he's likely to keep dropping. So it can depend on how far he has dropped (was it a really high preshot or was it fairly low) and how far along in the cycle is he? Honestly, 80 is a good number...but it looks like you are getting those greens super early in the cycle. Do you feed each time you get a green? I'm thinking the dose is too high because he shouldn't be going so low at +2...I assume you've been feeding which has steered him up into those lovely blues and made it look like his nadir is at +2. If you didn't feed then, I think you would have seen some even lower numbers and possibly a hypo.
I guess what I'm trying to say (in that long rambly paragraph I just posted) is that I think you may have too high of a dose. He's dropping quickly to low numbers early in the cycle. And I think you may be seeing some bouncing with those preshots...or maybe they're higher when you've had to steer. I think, if he was mine, I'd drop the dose back to 0.4 and monitor. Run a curve if possible, so we could see how it affects him. That's the dose that gave him some nice blues last time. That's just my opinion, though! What do you think?
If you're ever worried that his numbers are crashing down fast, post here and on Health and ask for help. There's plenty of experienced folks around here who have walked people through low numbers before and they will be happy to help you!