How to build a custom algorithm within Pricing Admin in Manage Algorithm?

Hi, Our client has a requirement with using different types of conversion rate types, other than corporate within Subscription Management. Our client will be mainly using the "corporate" rate type, which has already been configured within pricing, and is working as expected. However, with certain use cases they may be using a different conversion rate type such as "user". We have not been able to troubleshoot how to create an algorithm so that in certain cases a subscription can be created with the user rate type. Especially as this user rate type may changes and will not be constant, depending on