Notice period when changing within Mweb

I signed up for the Rain-LTE double data promotion last year. This promotion is coming to an end by 25 October and I made a call to Mweb this afternoon to change my product in time before I have to pay more for fewer data. I am considering the Cell-C LTE product. The sales agent told me that I will have to give one month's notice as I will be moving to a different product. By doing this, I will be paying for half the data at the same price for November.

When changing from ADSL to LTE last year, there was no notice period because the change was still within Mweb. I was not at the end of my ADSL contract yet and moved to a whole different type of internet. Now that I want to make a change, a notice period is suddenly applicable.

Can someone please confirm if this is in fact how this transaction will be handled? If so, I see no reason for me to stay with Mweb as I might as well just give a month's notice and go somewhere else.