Stripe payments
When you upgrade or downgrade
                We use Stripe for the shopping cart and Stripe takes your payment on the same day of each
                month.  That date is determined by the date you first bought the software.  Any upgrades or
                downgrades are dealt with in arrears.
                For example, if you first purchase the Entry level of Cloud Pricing on 1st January for 9 your
                first payment is 1st January.  If on 15th January you upgrade to the Premium level for 39 no
                further money is taken until 1st February.  Then on 1st February you will pay 39 for the next
                30 days use of the software in addition to the unbilled amount from 15th January to 1st
                February.
                So your payments will be:
                1 January 9
                1 February 54 (including the unbilled upgrade of 15 for the period 15/1 to 31/1)
                1 March 39
                Likewise, if you downgrade to a lower level a credit will be applied the next time your
                monthly payment is due.