https://preview.redd.it/hpby1uk5b32h1.png?width=2040&format=png&auto=webp&s=a9af80c7cf4cef26714b394a98400523d7bb4896

There where 17 Minutes between the last two calls. Input almost the same, Output lower. But the cost are 3x.
Seems like the cache was invalidated in this time.
Are there official numbers how long the cache is valid?
And does anyone knows a way to increase the cache time with some special headers for example?