If you wish to do so you certainly can switch from monthly to annual plan. To do that within your Insightful application just go to Settings → Billing → Subscription Plans.
Once there, click on the Annual Billing button in the upper right corner, choose the plan you wish to move to, and just hit the Subscribe button.
Keep in mind that we offer a 20% discount for annual payments!
If you swap to another plan in the middle of your billing cycle - our billing system will automatically recognize that and manage the prorated charge.
If you still need assistance with the matter, please contact our Support team and we'll happily assist you.