Delay in refreshing data from a data set

CMS Version

V4

Player Type

Windows

Player Version

V4

I am attempting to use a dataset to allow the content to be more dynamic so I can change the layout according to what I have defined as a period in the day (school setting). I have seen some examples and have tried to implement them by creating the dataset and using the dataset widget with a string element to display the name of the current period. This is just my test as eventually I would like to use the image field. The only problem is it seems to update about 15 minutes after the defined times. What settings affect this refresh?

My data set is as follows:

I have an upper row limit of 1 and the following filter:

DATE_FORMAT(NOW(), ‘%T’) < Time

Is there something wrong with my data or logic, or is there some kind of setting I can tweak to get it to refresh more promptly?

This is 4.1 or 4.0 CMS version ?

I know they’ve improved the data in real life on version 4.1

I have upgraded to 4.1 now and it still the same, I have even added another layout to cycle round with it but this has made no difference, on average the value changes after about 25 mins from the defined time.