The Period slider jumps to 15 when the BerPeriod is set to 15 in the script. So the time frames are ok.

You're defining H4, H1, etc. price series, but don't do anything with them. You cannot, because the stoch function from the TA library has no data series parameter. It just uses the current asset price series. Thus it can not support different time frames.

If you want the functionality of the stoch for different time frames, you can use the Normalize function or better, the Fisher transform. Both work with any data series. We can of course also implement a traditional stoch for different time frames in a future version. We had not done this so far because we did no see any real use for the stoch function.