Forgivable Seller Note and Investor Ownership Percentages

Does anyone know how a forgivable seller note interacts with common stock ownership percentages if you are raising outside equity? As a very simple example, if it is a 10M deal (5M Senior Note, 2.5M equity, and 2.5M forgivable seller note) but the seller note is ultimately "forgiven", do the equity providers own 25% of the common stock or 33% (assuming there is no "step up" in common stock). I am sure the answer to this is that it can be negotiated in several ways but I'm curious what is the more conventional wisdom/market terms around this. Thanks for any insight!