All EQ calculated on this website are meant for speakers at ear height. Due to HRTF (Head Related Transfer Function), sound coming from another height is perceived differenly : place one speaker at ear level and another under or above and alternatively play pink noise on each and listen for differences.
If the center loudspeaker is not at same height as L and R, then should it be equalised with a different target ? Question is open.
In a recording studio where I had to calibrate a main monitoring system with Genelec 1234 and a nearfield pair of PSI A17M, I had this problem. The Genelec were placed quite high, more than 15° above the PSI that were at ear level. For a similar sound balance, I had to ajust the EQ of the Genelec.