With a monthly subscription you pay the base price and are billed monthly, and with an annual subscription you pay once a year in exchange for a discount on the total amount. The listed price shows how much you're saving with an annual plan compared to the monthly, which in your case the average came out to $12.30/mo, or $147.60 for the total year you signed up for with annual billing.
If you want to change this, I suggest
contacting support directly and they can help you further.