Bit of a curate's egg there. The first instructor is teaching you to approach too low if my assumption is correct that you are using PAPIs to maintin a 3 degree glidepath. That's for instrument traffic - for a VFR 172 you need to be approaching steeper than that.
Main thing is not to be too fast at the point the approach is stabilised - on a calm day 60kts is plenty. You'll soon tell if you're too fast as the flare will go on and on before the aeroplane lands, floaty floaty down the runway, as it dissipates the excess speed before running out of energy and touching down (you do fully hold-off, don't you?).