The following bits are used for the XSHOOTER score flag:
======================================================== 
2^0	seeing < slit_width?	yes-->0	   
2^1	mean_airm<1.8?		yes-->0	   
2^2	flux_preserved?		yes-->0	(yes only if slit=5.0x11) 
2^3	mean_red>=0?		yes-->0	   
2^4	qc_s2n>=0?		yes-->0	   
2^5	n_sat<1000?		yes-->0	   
2^6	expno = nexp?		yes-->0	(1 if template aborted)

This scheme is applied to both science spectra and telluric standard spectra.