upgrade suscription

Hi! I currently have the home basic plan with just 1 doorbell, and recently buy another cam for the same location, so If I want to save recordings on both cams I need to upgrade the plan. The thing is that I recently renew the home basic (Octuber) and if I want to upgrade to the next level (home standard) apparently I have to pay full price  Do you know if I can upgrade paying just the difference between both plans?