Renewal notice shows fees that are very confusing

My renewal of subscription notice indicates that I have to pay $69.99 for one year subscription and $99.99 for two years. My friend in the USA paid for the subscription last year about $39.95 and could share it with a second computer (mine). Her latest renewal notice (same date naturally as mine) indicates $39.99 for one year and $69.99 for two years. It does not now mention whether this is for more than one computer. Please tell me why I should be called upon to pay so much more for the same subscription than my friend for the exact same services. Please tell me also whether my friend can apply her renewed subscription to another computer like last year.

Nice offer here: → http://www.avast.com/products

I ended up taking AIS at the price offered at the link above last time it was offered.

For reasons I can’t fully fathom, the US dollar price is usually a bargain compared to the currency of my home country (see below). I paid USD 69.99 using PayPal, opted to let my Bank do the currency exchange (which may not be the best option in every case) and the total bill was less than AUD 70.00.