This is buy order.

Why is the order updated 500 minutes ago, and not updating again for 800 minutes, when the update interval is 15 minutes?

I started auto trader 7 minutes ago to clear some backlog in inventory and I noticed this on a few of the buy orders...

Order installation interval means bot will collect new data and install new orders. No need to do this very frequently, besides if you have a lot of items to sell and not realized ISKs in wallet.

Orders not updated as fast as possible. Bot takes into consideration update count per each order and if you updated order like 5 times already and did not sell anything it is pointless to waste time and money and update more.