Give an example. You could calibrate out the +- 30ppm frequency deviation in software but how would you propose dealing with the +- 50ppm stability with temperature?
In ham radio equipment they often use a small adjustable variable trimmer cap in place of one of the fixed padding caps to fine tune the resonance frequency of the crystal +/- a few KHz, but that wouldn't have any improvement for the tempo stability variation of the crystal, that you live with or control the environmental temperature of the crystal.
Lefty