You're really asking two questions.
1) can seller financing have a tax impact on the seller, and
2) can the seller change the contract late in the game.
For the answer to #1, it's likely your seller is attempting to complete a 1031 tax deferred exchange. if that is the case there are implications to his taxes, and how his seller financed note is structured and handled will make a difference to him. You can get more details in this article:
Regarding #2. If you both have committed to the deal and all contingencies have been removed it is likely you both have a contractual obligation that cannot be changed without mutual consent. However, we don't have enough details about your particular transaction to understand if that is the case here.
You should consult with an attorney to review your contract in order to determine where you stand in the transaction. You may also want to consult your accountant or financial adviser to review the changes in the financing to see if there really is a significant impact to you.
Best of luck!
Allan S. Glass
ASG Real Estate Inc. Â®
149 S. Barrington Ave, Suite #660
Los Angeles . CA 90049
Direct: 213.973.8637 (213.97.FUNDS)
CA License: 01154002
Visit Allanâ€™s Blog: http://allanglass.featuredblog.com