I retained the case numbers from the default DOE-2 expression for MIN-FLOW-RATIO below. The switch statement is based on symbol values according to the symbol table for system TYPE. The symbol tables are found in a file called BDLKEY.OUT which, for eQUEST 3-65, is found in Documents -> eQUEST 3-65 Data -> DOE-2.
A short cut to determining which case numbers to use with switch statements is to enter a user expression for an appropriate keyword. For system TYPE, you could enter, ?#SV(#P("TYPE"))? as a user expression for a zone keyword such as MIN-FLOW/AREA to see which symbol value matches the zone?s system type.

~Bill