I agree with Chuck.
Keeping your eyes fixed on the end of the runway is absolute bilge. First off, as you progress to 'real' aircraft you will find that the view ahead reduces to nil in the flare (often the whole approach). Secondly, how can you gauge your height from looking at a point that may be 3000ft ahead of you? What if you land on a runway much shorter or longer.. won't the picture look wrong leading to errors?
It always amazes me how little you need to see to gauge the flare height. Your brain is very good from picking up little clues from whatever view out you have. Don't over analyse just DO IT .
A couple of points that helped me whilst training were:
1. Forget the ASI once in the flare - really, the 'numbers' part of the flight is over at this point it’s all about feel from here in.
2. As an instructor once said to me 'Never rush the last two seconds of any flight' - good advice!
Kingy