The first arc of Gacha Gacha (capsule) deals with multiple personalities similar to Change 123. In each story, the male lead is trusted with keeping this fact a secret from their classmates. This results in both our young friends being put through some tough circumstances for the girl they have fallen for.
The first half of Gacha Gacha is about an ecchi romantic comedy about a boy and a girl with split personalities.
Uwagaki is an an ecchi romantic comedy about a boy and a girl who is literally split into two identical people.
Both mix ecchi harem antics with a sweet romance and a touch of science fiction.
Same author, similar artwork, both are about school romance, and they have to go thru some stuff before they realise their feelings for each other (main chars).
Love Automation is a One Shot, 39 pages, while Gacha Gacha consists of 2 long parts.