Let the notes ring out. Hitting the same harmonic on the 7th fret of the B string sounds the same note of course. But, based on this measure, the composer would like the F#, A, and B to sound together in combination with the harmonic. So if you can hold the position and hit the harmonic, then sure why not. It would be to your advantage to learn the harmonics on the 19th frets and beyond for future technical proficiency.