In general, you only need to specify these two parameters: the beginning of the period and the end of the period (pic. 1)
The "Periodicity" parameter determines how the data will be grouped when the query is running. For example, if we specify "Recorder", then the data will be grouped by the registrar of the register (pic. 2)
In your case, to get the correct balance values at the beginning and end, it will be enough to specify the periodicity of "Period" (pic. 3)
And yet - you can not specify the Periodicity value at all, this is not a mandatory parameter. In any case, you will receive the correct balances for the period you set.