Hi
1. You just need to make one purchase and use it on all of these websites. The only limitation is that for each purchase, you will only get support from us for one site only. So if you need support for second site for example, you will need to purchase a second license
2. Both support and update are within 12 months. After 12 months, the extension will still work OK on your site. However, if you want to continue updating to new version, you will need to re-purchase it
Regards,
Tuan