We have a scenario where the investor paid in Class A, now they are doing an Additional Contribution to Class B, but we can't send out a Class Change document as the payment is pending in Class B.  (We could have done the Class Change first and then added the Additional Contribution, but we missed doing that).
The other scenario is where an investor wants to send a lump sum check and needs to increase their subscription amount and the system will not let us add an Additional Contribution as the first payment is pending.