Bisexual is defined as attraction to more than one gender, where gender is a component of the attraction. So if you 96% like one gender, 3% another, and 1% yet another, that's bi. If you're 60/40, that's bi too. Bi = multiple genders where gender plays a factor. It has never meant only 50/50.
Pansexual is attraction to people where gender doesn't play a role. Pansexuals' patterns may look like a bisexual's patterns because they date across genders, but the attraction matrix is different.
Finsexual (Gynesexual) is attracted to feminine traits generally. Whether penis or vagina, it is the femininity they like. I can speak to this as this is me. I like feminity, not necessarily women particularly. I use bisexual as shorthand because most people "get" that.