Linux server management debian 10 and centos dhcp service host-name based Client Classing

Question

I want to allocate a client's IP address based on the host-name provided by the client, but the results are often unpredictable.
I have tried to imitate the Client Classing in dhcpd.conf(5) by assigning
clients with host-name "Debian-xx" to the 192.168.100.0/24 subnet
clients with host-name "Centos-xx" to the 192.168.1.0/24 subnet.
I am using DHCP version 4.4.1. When I check the logs using "dhcpd -d", I noticed that the classing is not taking effect or there are errors. For example, the "Centos-xxx" clients might be assigned to the 192.168.100.0 or 192.168.255.0 subnet, and the assignments seem to be inconsistent.

This is the content of my dhcpd.conf file.

default-lease-time 10;
use-host-decl-names on;
max-lease-time 20;
authoritarive ;
log-facility local2;

class "centos-server"{
    match if (substring(option host-name ,0,6)="Centos") ;
}

class "debian-server"{
    match if (substring (option host-name  ,0,6)="Debian") ;

}

subnet 192.168.0.0 netmask 255.255.0.0 {

    option routers 192.168.0.2;

    option subnet-mask 255.255.255.0;
    pool{
    allow members of "centos-server";
    range 192.168.100.1 192.168.100.254;
    }
    pool{
    allow members of "dbian-server";
    range 192.168.1.1 192.168.1.254;
    }
    pool{
    range 192.168.255.1 192.168.255.254;
    }

}
on commit {
log(debug, concat("test for   ",  substring(option host-name,0,6 ) ));
 if ( ( substring( option host-name , 0, 6 ) ="Debian") ) {
log(debug,"Debian!");
}
else if ( ( substring( option host-name , 0, 6 ) ="Centos") ) {
log(debug,"Centos!");
}
else {
log(debug,"i dont konw");
}

}

This is the content of my dhclient.conf

send host-name = gethostname();
request subnet-mask, broadcast-address, time-offset, routers,
    domain-name, domain-name-servers, domain-search, host-name,
    dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
    netbios-name-servers, netbios-scope, interface-mtu,
    rfc3442-classless-static-routes, ntp-servers;

I experimented with modifying the expression after "match if," such as using "or (1=1)," but the client may still not be assigned to that class.
I tried to see if it was an issue with "host-name" and "option host-name," but it doesn't seem to be the key issue.
I suspect there is an error in the conditional expression within the class, but the commit logs, I found that the log results alternated between "Centos!" and "I don't know".
I searched for related issues, such as this link dhcpd class match on hostname or mac address, but it seems that the answers did not provide a good solution to the problem.
I want to know where my mistake lies, how to modify it, or if there are websites that provide solutions.

If you can provide assistance, I would be extremely grateful.