Price increase of HP Instant Ink

[saiwong]

I just got the price increase email today.

Question: If I move to a lower priced plan, does the charge begin at the start of the new month or will they start charging immediatey.

For example, if I currently have used X pages this month (which is currently below the plans limit)
and move down to a lower plan that allow up to Y pages (where Y < X)
do they charge me for excess pages over the plan limit ?

using actual numbers, just say I have used 20 pages this month and the plan limit is say 50 pages. Everything ok so far.

However, if I switch down to a plan that only allows 10 pages, do I immediately go over my plan when I switch over and get

charge for the excess or am I ok and changes only take effect the next month ?

[UnhappyPH]

I understand that the new charges will be from the start of the next billing period. 
So, you wouldn't have an overage this period, but you wouldn't start paying the reduced price until your next billing day.