the endings 7-A and 7-B are different depending on whether you answered 'I was happy' or 'I was sad' in the beginning of the nougat route. if you use the skip option while playing, you'll see some new dialogue even though you'll still end up on the same ending/s. Once you find a dialogue that reveals a name of a girl (not a♡ btw), you'll finally unlock Chihaya's Extra Story^^