Hey,
Billing for IPv4 will begin on Feb 1, so you’ll see this charge reflected in your March invoice, since charges will be from the previous month. If your bill is $2.06, it’s likely that the charge will be carried forward into the next few months (April and May) until $5 is reached (probably in the May invoice ~$6.18 assuming no other charges are incurred), at which point we will charge the credit card associated with your account.
Hope that’s clearer!