By default YFI Hotspot Manager Voucher.pm in the rlm_perl_module came with hardcoded time zone to +02:00. This can cause an error or inaccuracy in the AAA process. So for the best setup result that is you should change it to your suite. To change this you can edit the file by typing this command into the terminal (Ubuntu Distro & standard installation of YFI).

The first,

$sudo nano /usr/local/etc/raddb/rlm_perl_modules/Voucher.pm

Go with search to the line than contain my $time_zone = '+02:00'; and change the +02:00 into your time zone.

The second,

$sudo nano /usr/local/etc/raddb/rlm_perl_modules/conf/settings.conf

Find the tag <timezone>+02:00</timezone>, and change into your time zone.

Save and restart radiusd and the NAS that you use. In this case i'm using coovaChilli as the NAS.

$sudo service radiusd restart && sudo service chilli restart

You're good to go.