@KamWest unfortunately if you change your plan midway through your existing plan cycle, then you'll lose the remaining amount. Public Mobile is a straight and true prepaid provider. You get what you pay for. There's no billing, there's no prorated system. I recommend if you're going to change your plan, then have it set up for the next cycle. This way you don't lose out on any of the money you already paid.
Technically you can switch your plans any time and as often as you like, but you just need to take note of what I mentioned above, every time you change your plan, you'll need to pay full price for the new plan you're switching too, and if it's mid way through an existing month/cycle then you'll always lose the remaining amount you paid for. Again recommend you change your plans at the end of each cycle (this you can have the system set that up automatically for you).
The switch is pretty much immediate, I usually wait about 3 minutes, then log back in to My Account to make sure the new plan is showing. Basically once the payment is processed then the new plan is activated.
Also, keep in mind, if you're currently on some type of promo plan (usually any of the ready made plans), then these plans can expire at anytime, so if you switch plans, and then your prior plan is no longer being offered, then you'll have to find a completely new plan, you can't ask PM to give you back your prior plan that is no longer being offered. So I guess you'll have to think if adding that additional 3GB is really needed, I mean how much do you plan on doing that'll require another 3GB of data? Just don't assume after switching plans that your prior plan will be there waiting for you when you want it back again.
