What calculates the MAILQUEUE_BATCH_PERIOD

I have a list which has approx. 500 users. I want to send 20/day. I have the following settings:
define(‘MAILQUEUE_BATCH_SIZE’, 20);
define(‘MAILQUEUE_BATCH_PERIOD’, 82800); // 23h

I wanted to sent them at 9:15AM via cron, but my cron did not trigger correctly. I finally got if figured out and started the send at 1:30 PM. I want to change the send time to 9:15. But no matter what I change in the config file, or directly in the DB, nothing changes the "limit reached.
next batch of 20 in XX hours XX mins. Which is approx. 1:30PM.

My Question… This section has to be looking at some data to calculate when it is suppose to restart. Where is this data? Where is the mailqueue batch period data stored, or how is it calculated. Someone has to know this.

It has to be somewhere. It cant be magic.

Start time (stored somewhere)
Mailqueue batch period (starts the time from what time…also stored somewhere)
Restart the next batch (stored or calculated)

I figured it out! A little crude, but it worked perfectly. I was able to “reset” the mailqueue batch period by updating the date/time in the “entered” row in the _usermessage table directly in MySQL.

I replaced 2025-06-12 13:32:00 with 2025-06-12 09:14:00. Which basically restarted the Batch period to 9:14:00. So now it runs basically at 9:15 AM instead of 1:30PM.