Carlton has a pretty normal looking SS for an unregulated fd kitty.
He is seeing green every so often and because he is not used to the lower numbers, his body still thinks the higher numbers are the normal numbers, his body panics and dumps stored glucose and regulatory hormones into his system and sends to BGs up higher again. Bounces can last from 1 to 6 cycles so this is why you see the blues, yellows and pink BGs. The more often he can stay in the greens, the quicker his body will recognise them as being the normal numbers and then hopefully he will stop bouncing.
Just keep following the SLGS method. FD takes patience and it’s a marathon not a race.
The other option is to follow the tight regulation protocol. You can find out about that at the top of the Lantus page in the yellow stickies.