did you try to do what i told you to do before? do not set alt_source to 1. keep it pointing to baro.
then set
EK2_RNG_I_GATE,500
EK2_RNG_M_NSE,0.2
EK2_RNG_USE_HGT,70
EK2_RNG_USE_SPD,6
make sure your rangefinder settings are also correct for tfmini - RNGFND_MAX_CM and RNGFND_MIN_CM. i look at mine and for some reason i left RNGFND_MAX_CM set to 600 - it was apparently a reliable range for outside, it looks like. not sure why it is a half of 12m range it should do but, still, it works fine.
arm model and look in the MP screen in the live values ‘status’ window at the value named ‘sonarrange’ - point model around and you should see there correct readings in meters - 0.3 for 30cm, 1 for 1m, etc.
if done as i tell you above it will sit rock solid at required altitude with no deviations. yours is not doing it at all, so, something is wrong.
also check my post there - Copter-3.6.1-rc1 is available for beta testing
follow the required steps for tfmini setup.