Changing broadband product

[#1]

I am on BbYW opt 2, and for the 3rd month in a row i am near to exceeding my usage with several weeks left until the end of this billing month!
I would like to upgrade to BbYW Opt 3.
If I do this, when will the new usage allowence come into effect? Immediately or in the next billing month?
Many thanks

[#2]

Generally it will be at the start of your next billing period, I think you can request it to be done sooner but you will be charged the pro-rated extra.

[#3]

I have ticked the "pay as you go" box in the "upgrade my usage" section. I have not applied to upgrade my product yet.
Can someone from Plusnet please confirm that if I go over 15Gb now, I will be billed an extra 98p per gigabyte?
Thanks

[#4]

Yep, that's correct. On Option 2 you'll be billed 98p per GB if you are on flex. Have a look on this page for the information about this.
If you wanted to upgrade to Option 3, then it would happen nearly straight away, you'd need to pay the pro-rata difference between the 2 products to make the change.

[#5]

@adiewoo

Quote

Generally it will be at the start of your next billing period

IIRC upgrades happen straight away but downgrades are postponed until your next billing date.