It's not really about taking the extra 20% it's just easier to value what that contribution was and is now worth that way. I also think one last thing to consi

It's not really about taking the extra 20% it's just easier to value what that contribution was and is now worth that way. I also think one last thing to consider: was this money lent with the possibility of it never being repaid, or was this a loan that the founder/s would have carried with them if the business failed? If there was never any risk that you would lose the money then I think that lessens what you should expect to receive for it.