Hello @kaiyito,
Currently, it is billed per calendar day as noted in the FAQs at one point it used to be billed in a 24hr period but that has since changed. Sometimes when reading through the community forum you also have to look at the date of the information you are reading because of constant changes not all discussions will apply.
Say, if I start roaming in the US at 7pm on Friday and get back into Canada at 5pm on Sunday. How many roaming days does that count?
To answer your question you will be charged for 3 days.
