I'd appreciate your thoughts on how best to structure plans for the following use case.

Plan A - 60 the first year, and 40 each year thereafter (which of course easily structured using the first price and regular price parameters)

Plan B - 70 for the first year, and 50 each year thereafter (Plan B offers additional features)

If someone is six months into their first year on Plan A, but decides that they want to upgrade to Plan B, and I have the options setup to prorate the remaining value, how does CBSubs handle this?

Does it upgrade to the partial remaining first year - e.g. prorate 30 remaining on the first year of Plan A, apply it to the 35 remaining of the first year of Plan B and charge the net 5, and switch to the year thereafter charge of 50 in plan B after the remaining 6 months has expired?

Thanks - I read through that, and understand the residual value calculation in normal circumstances - where we swap the value of an unexpired term into pay for a full term of a replacement plan.

However, in this case, Plan A has a different price for the first year than the price for the second year and thereafter.

Plan B also has a different price for the first year than the price for the second year and thereafter - and it has more features.

If I am halfway through the first year on plan A, which I paid 60 for I know that I am going to be charged a lower price in the second year if I renew, a price of 40.

But I haven't completed my first year of membership. If I want to upgrade to plan B for 70 the first year, and 50 per year after, there could be different ways that upgrade logic could work.

Logic #1: I get credit for 30 of my unexpired plan A first year with six months to go, and it is applied to a new full first year of plan B. So my one year count starts again, and I pay 40 for that full year at the upgraded level.

Logic #2: I get credit for 30 of my unexpired plan A first year with six months to go, and it is applied to six more months to finish off a full first year with Plan B. Plan B is prorated for the remaining first year at 35, my 30 is applied in residual value, and I pay 5. In six months, my price is reduced for subsequent years and I pay 50 per year thereafter with plan B.

Logic #3: I get credit for 30 of my unexpired plan A first year with six months to go, and it is applied to the renewal rate for Plan B, which is 50. I pay the 20 net to start a new one year cycle.

So in essence, my question gets down to how residual value is applied when you go from one split Plan to another.

Or, if you have a thought to structure it differently to anticipate this issue.