Understanding Society User Support

I am looking for information about how the hiqual_dv variable is derived. I have found on the website the following information:
"The code to derive hiqual_dv in Wave 1 is as follows: gen ${wave}hiqual_dv=-9 replace ${wave}hiqual_dv=1 if ${wave}qfhigh1 | ${wave}qfhigh2 replace ${wave}hiqual_dv=2 if ${wave}qfhigh>=3 & ${wave}qfhigh<=5 replace ${wave}hiqual_dv=3 if ${wave}qfhi"

I am interested in how the later values of hiqual are derived after the value of 2 and wondered if the remainder of this code was available?

I am particularly interested as in the dataset I have tried to identify how the variable is derived but it is not so clear since in the data some individuals who are classified as having A levels by the hiqual variable are reported to have GCSEs/ O level as their highest qualification according to the qfhigh variable. I am therefore unsure of how the individuals are reported to have A levels since the hiqual variable is derived from the qfhigh variable. Any further information on these variables would be very much appreciated.