I know this is frustrating but Lucy is bouncing. You are seeing pinks but you're also seeing some blues. When Lucy drops into the blues, she then bounces. Once she clears the bounce, then you might want to consider increasing.
Regarding the vomiting, by any chance are you feeding either beef or fish at the times Lucy has vomited? Gabby doesn't do well with beef and will throw up if I feed it. Beef and fish are common food allergies for cats.