Combine Lock Options on Android

I’m using BW on my Android. but I feel kike typing my Masterpassword too often. I would like to see some combination of Password and Biometrics. Only using biometrics seems to be too unsafe. For example something like this:
If time since last PW-unlock is greater than X
{ask for PW}
else if time since last Biometric-unlock is greater than Y
{ask for Biometric}
with X>Y