Question about neck

[planetjimi]

Hi, I just got a warmoth neck. I went to level it and straightened the neck using my notch straight edge (reads the actual fretboard). The neck looks normal up until I got to the 19th fret. The fingerboard started to fall away on the 20th. and 21st. frets. Therefore when leveling the frets the last two frets did not get touched. Obviously it does not buzz when played cause they are lower, but it is harder to hammer on those frets because the frets are lower. Anyone ever experience this? Should I keep filing the uppers frets until those two are reached?
Thanks,
Jimi

 

[Cagey]

Hammer harder. There's supposed to be a couple/few thousandths of fall away at the end of the board. The truss rod can't compensate down there.