I had a bit of a shock this morning:

It's approaching the end of my billing\data cycle with snap.   We have 135GB (grandfather plan with a promo add-on + 100GB add on) to play with monthly, which is usually plenty, but this month I noticed it was getting quite close a few days ago. So I set all download\uploads to a schedule between 1:15am and 6:45am.  This seemed to work fine and reduced the household consumption to an acceptable rate - I kept an eye on it and it looked like we would be fine to the end of the month.  

This morning though I get an email that we're over our data cap and overage charges will apply. When I log in to check how much it's a good 23GB which is a bit of a shock and according to snap FAQs will cost a good $40?  When I look at the usage it seems that as soon as you hit your data cap it starts counting what should be free data from 1am-7am as overage data.

So a couple of questions for snap:

1) Should 1am - 7am data be charged when you hit your cap? The wording when I log into my account at the top is just "You currently have unlimited data between 1am and 7am."

2) If I change from a 100GB add-on to a 250GB add-on and select the "apply now" option, will I still need to pay the overage charges?