LDAP.mac -- Why use $$$WindowsCacheClient instead of $$$ISWINDOWS?

Reference: sample LDAP code routine LDAP.mac

Some IF statements reference macro $$$WindowsCacheClient as a boolean flag to mark if the client calling the LDAP server is running Windows. Other IF statements reference $$$ISWINDOWS. Are they not the same thing? That is, does the routine need $$$WindowsCacheClient at all?

Examples:

#define WindowsCacheClient 1

 if $$$WindowsCacheClient,$$$WindowsLDAPServer {
s Status=##Class(%SYS.LDAP).Binds(LD,"",$lb(Username,Domain,Password),$$$LDAPAUTHNEGOTIATE)
i Status'=$$$LDAPSUCCESS {
s Status=Status_",ldap_Binds(AdminDN) - "_##Class(%SYS.LDAP).Err2String(Status)
g Done
  }

 i $$$ISWINDOWS,$$$UseSecureConnection {
s LD=##Class(%SYS.LDAP).Init($$$LDAPServer,636)
 } else {
s LD=##Class(%SYS.LDAP).Init($$$LDAPServer)
 }