Equation of State Switching is not working

I'm using the python wrapper ctREFPROP. I'm been looking for ways to compare different equations of states but I've run into this problem where the Peng-Robinson equation of state will not activate or deactivate in response to the PREOSdll function call. I'm working on a much larger code but the following illustrates my problem just fine and is taken from another issue.

import os
from ctREFPROP.ctREFPROP import REFPROPFunctionLibrary

root = os.environ['RPPREFIX']
RP = REFPROPFunctionLibrary(root)
RP.SETPATHdll(root)
RP.FLAGSdll("Cache", 3)

def props(inputs):
    usePR, hOut, key1, val1, key2, val2, hFld, z = inputs
    if usePR:
        RP.PREOSdll(2)  # 2 Use Peng-Robinson equation for all calculations
    else:
        RP.PREOSdll(0)
    RP.SETFLUIDSdll(hFld)
    hIn = key1+key2
    return RP.REFPROPdll('', hIn, hOut, RP.MASS_BASE_SI, 0, 1, val1, val2, z).Output[0]

string = 'REFPROP::NITROGEN[0.80]&HYDROGEN[0.20]'

components = string.split("::")[1].split('&')
fluid_names = [x[0: x.find('[')] for x in components]
fractions = [float(x[x.find('[') + 1: x.find(']')]) for x in components]
hFld = ";".join(fluid_names)

samples_1 = [True, 'H', 'P', 1011620, 'T', 373.15, hFld, fractions]
samples_2 = [False, 'H', 'P', 1011620, 'T', 373.15, hFld, fractions]

print(props(samples_1))
print(props(samples_2))

This is what it prints out for me:

468310.40330816555 468310.40330816555

Also, given that the first run is supposed to use Peng-Robinson and the second run is supposed to use the default model, I'd expect that this would of provided a different answer. I encounter the same lack of action when using FLAGSdll("PR", 2). Along these same lines, is there a general method to determine which equation is applied at a given time. As querying:

    for i in range(len(z)):
        out = RP.REFPROPdll('', 'TP', 'DOI_EOS(' + str(i + 1) + ')', RP.MASS_BASE_SI, 0, 1, val1, val2, z)
        print("Mixture: {}, Equation of state applied ({}): DOI: {}".format(hFld, i, out[2]))

Doesn't provide a different DOI in cases when I am seemingly able to change the EOS: For example, using the SETMODdll function to change to change hcomp="PRT". Has the PREOSdll function been made no longer functional?

usnistgov / REFPROP-wrappers

Equation of State Switching is not working #509