The fix that you provided does not seem to work for users of the reset snippet fix. It is correct that its not being correctly initialized, Area age seems to be default to 15 and if you have a reset time greater than that the area does not reset. I know i posted one way to fix it a while back which was to make the age 60, since then i have changed what i did and in the function load_resetfreq added the following line
tarea->reset_frequency = fread_number( fp );
tarea->age = tarea->reset_frequency;
By making the area age the same as the reset frequency at boot up, the area is reset and works as intended. The other fix as supplied by Remcon does not work on my version of smaug, which uses the reset fix snippet by Samson thats posted on this site. I don't know what exactly is different other than i do not have a function called update_room_reset. This might be the reason why its not resetting the area. Dont know really.